This is gettext.info, produced by makeinfo version 4.6 from
gettext.texi.

INFO-DIR-SECTION GNU Gettext Utilities
START-INFO-DIR-ENTRY
* gettext: (gettext).                          GNU gettext utilities.
* autopoint: (gettext)autopoint Invocation.    Copy gettext infrastructure.
* gettextize: (gettext)gettextize Invocation.  Prepare a package for gettext.
* msgattrib: (gettext)msgattrib Invocation.    Select part of a PO file.
* msgcat: (gettext)msgcat Invocation.          Combine several PO files.
* msgcmp: (gettext)msgcmp Invocation.          Compare a PO file and template.
* msgcomm: (gettext)msgcomm Invocation.        Match two PO files.
* msgconv: (gettext)msgconv Invocation.        Convert PO file to encoding.
* msgen: (gettext)msgen Invocation.            Create an English PO file.
* msgexec: (gettext)msgexec Invocation.        Process a PO file.
* msgfilter: (gettext)msgfilter Invocation.    Pipe a PO file through a filter.
* msgfmt: (gettext)msgfmt Invocation.          Make MO files out of PO files.
* msggrep: (gettext)msggrep Invocation.        Select part of a PO file.
* msginit: (gettext)msginit Invocation.        Create a fresh PO file.
* msgmerge: (gettext)msgmerge Invocation.      Update a PO file from template.
* msgunfmt: (gettext)msgunfmt Invocation.      Uncompile MO file into PO file.
* msguniq: (gettext)msguniq Invocation.        Unify duplicates for PO file.
* xgettext: (gettext)xgettext Invocation.      Extract strings into a PO file.
* ISO639: (gettext)Language Codes.             ISO 639 language codes.
* ISO3166: (gettext)Country Codes.             ISO 3166 country codes.
END-INFO-DIR-ENTRY

   This file provides documentation for GNU `gettext' utilities.  It
also serves as a reference for the free Translation Project.

   Copyright (C) 1995-1998, 2001-2003 Free Software Foundation, Inc.

   Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

   Permission is granted to copy and distribute modified versions of
this manual under the conditions for verbatim copying, provided that
the entire resulting derived work is distributed under the terms of a
permission notice identical to this one.

   Permission is granted to copy and distribute translations of this
manual into another language, under the above conditions for modified
versions, except that this permission notice may be stated in a
translation approved by the Foundation.


File: gettext.info,  Node: Top,  Next: Introduction,  Prev: (dir),  Up: (dir)

GNU `gettext' utilities
***********************

This manual documents the GNU gettext tools and the GNU libintl library,
version 0.13.

* Menu:

* Introduction::                Introduction
* Basics::                      PO Files and PO Mode Basics
* Sources::                     Preparing Program Sources
* Template::                    Making the PO Template File
* Creating::                    Creating a New PO File
* Updating::                    Updating Existing PO Files
* Manipulating::                Manipulating PO Files
* Binaries::                    Producing Binary MO Files
* Users::                       The User's View
* Programmers::                 The Programmer's View
* Translators::                 The Translator's View
* Maintainers::                 The Maintainer's View
* Programming Languages::       Other Programming Languages
* Conclusion::                  Concluding Remarks

* Language Codes::              ISO 639 language codes
* Country Codes::               ISO 3166 country codes

* Program Index::               Index of Programs
* Option Index::                Index of Command-Line Options
* Variable Index::              Index of Environment Variables
* PO Mode Index::               Index of Emacs PO Mode Commands
* Autoconf Macro Index::        Index of Autoconf Macros
* Index::                       General Index

 --- The Detailed Node Listing ---

Introduction

* Why::                         The Purpose of GNU `gettext'
* Concepts::                    I18n, L10n, and Such
* Aspects::                     Aspects in Native Language Support
* Files::                       Files Conveying Translations
* Overview::                    Overview of GNU `gettext'

PO Files and PO Mode Basics

* Installation::                Completing GNU `gettext' Installation
* PO Files::                    The Format of PO Files
* Main PO Commands::            Main Commands
* Entry Positioning::           Entry Positioning
* Normalizing::                 Normalizing Strings in Entries

Preparing Program Sources

* Triggering::                  Triggering `gettext' Operations
* Preparing Strings::           Preparing Translatable Strings
* Mark Keywords::               How Marks Appear in Sources
* Marking::                     Marking Translatable Strings
* c-format Flag::               Telling something about the following string
* Special cases::               Special Cases of Translatable Strings
* Names::                       Marking Proper Names for Translation

Making the PO Template File

* xgettext Invocation::         Invoking the `xgettext' Program

Creating a New PO File

* msginit Invocation::          Invoking the `msginit' Program
* Header Entry::                Filling in the Header Entry

Updating Existing PO Files

* msgmerge Invocation::         Invoking the `msgmerge' Program
* Translated Entries::          Translated Entries
* Fuzzy Entries::               Fuzzy Entries
* Untranslated Entries::        Untranslated Entries
* Obsolete Entries::            Obsolete Entries
* Modifying Translations::      Modifying Translations
* Modifying Comments::          Modifying Comments
* Subedit::                     Mode for Editing Translations
* C Sources Context::           C Sources Context
* Auxiliary::                   Consulting Auxiliary PO Files
* Compendium::                  Using Translation Compendia

Using Translation Compendia

* Creating Compendia::          Merging translations for later use
* Using Compendia::             Using older translations if they fit

Manipulating PO Files

* msgcat Invocation::           Invoking the `msgcat' Program
* msgconv Invocation::          Invoking the `msgconv' Program
* msggrep Invocation::          Invoking the `msggrep' Program
* msgfilter Invocation::        Invoking the `msgfilter' Program
* msguniq Invocation::          Invoking the `msguniq' Program
* msgcomm Invocation::          Invoking the `msgcomm' Program
* msgcmp Invocation::           Invoking the `msgcmp' Program
* msgattrib Invocation::        Invoking the `msgattrib' Program
* msgen Invocation::            Invoking the `msgen' Program
* msgexec Invocation::          Invoking the `msgexec' Program
* libgettextpo::                Writing your own programs that process PO files

Producing Binary MO Files

* msgfmt Invocation::           Invoking the `msgfmt' Program
* msgunfmt Invocation::         Invoking the `msgunfmt' Program
* MO Files::                    The Format of GNU MO Files

The User's View

* Matrix::                      The Current `ABOUT-NLS' Matrix
* Installers::                  Magic for Installers
* End Users::                   Magic for End Users

The Programmer's View

* catgets::                     About `catgets'
* gettext::                     About `gettext'
* Comparison::                  Comparing the two interfaces
* Using libintl.a::             Using libintl.a in own programs
* gettext grok::                Being a `gettext' grok
* Temp Programmers::            Temporary Notes for the Programmers Chapter

About `catgets'

* Interface to catgets::        The interface
* Problems with catgets::       Problems with the `catgets' interface?!

About `gettext'

* Interface to gettext::        The interface
* Ambiguities::                 Solving ambiguities
* Locating Catalogs::           Locating message catalog files
* Charset conversion::          How to request conversion to Unicode
* Plural forms::                Additional functions for handling plurals
* GUI program problems::        Another technique for solving ambiguities
* Optimized gettext::           Optimization of the *gettext functions

Temporary Notes for the Programmers Chapter

* Temp Implementations::        Temporary - Two Possible Implementations
* Temp catgets::                Temporary - About `catgets'
* Temp WSI::                    Temporary - Why a single implementation
* Temp Notes::                  Temporary - Notes

The Translator's View

* Trans Intro 0::               Introduction 0
* Trans Intro 1::               Introduction 1
* Discussions::                 Discussions
* Organization::                Organization
* Information Flow::            Information Flow
* Prioritizing messages::       How to find which messages to translate first

Organization

* Central Coordination::        Central Coordination
* National Teams::              National Teams
* Mailing Lists::               Mailing Lists

National Teams

* Sub-Cultures::                Sub-Cultures
* Organizational Ideas::        Organizational Ideas

The Maintainer's View

* Flat and Non-Flat::           Flat or Non-Flat Directory Structures
* Prerequisites::               Prerequisite Works
* gettextize Invocation::       Invoking the `gettextize' Program
* Adjusting Files::             Files You Must Create or Alter
* autoconf macros::             Autoconf macros for use in `configure.in'
* CVS Issues::                  Integrating with CVS

Files You Must Create or Alter

* po/POTFILES.in::              `POTFILES.in' in `po/'
* po/LINGUAS::                  `LINGUAS' in `po/'
* po/Makevars::                 `Makefile' pieces in `po/'
* configure.in::                `configure.in' at top level
* config.guess::                `config.guess', `config.sub' at top level
* mkinstalldirs::               `mkinstalldirs' at top level
* aclocal::                     `aclocal.m4' at top level
* acconfig::                    `acconfig.h' at top level
* config.h.in::                 `config.h.in' at top level
* Makefile::                    `Makefile.in' at top level
* src/Makefile::                `Makefile.in' in `src/'
* lib/gettext.h::               `gettext.h' in `lib/'

Autoconf macros for use in `configure.in'

* AM_GNU_GETTEXT::              AM_GNU_GETTEXT in `gettext.m4'
* AM_GNU_GETTEXT_VERSION::      AM_GNU_GETTEXT_VERSION in `gettext.m4'
* AM_PO_SUBDIRS::               AM_PO_SUBDIRS in `po.m4'
* AM_ICONV::                    AM_ICONV in `iconv.m4'

Integrating with CVS

* Distributed CVS::             Avoiding version mismatch in distributed development
* Files under CVS::             Files to put under CVS version control
* autopoint Invocation::        Invoking the `autopoint' Program

Other Programming Languages

* Language Implementors::       The Language Implementor's View
* Programmers for other Languages::  The Programmer's View
* Translators for other Languages::  The Translator's View
* Maintainers for other Languages::  The Maintainer's View
* List of Programming Languages::  Individual Programming Languages
* List of Data Formats::        Internationalizable Data

The Translator's View

* c-format::                    C Format Strings
* objc-format::                 Objective C Format Strings
* sh-format::                   Shell Format Strings
* python-format::               Python Format Strings
* lisp-format::                 Lisp Format Strings
* elisp-format::                Emacs Lisp Format Strings
* librep-format::               librep Format Strings
* smalltalk-format::            Smalltalk Format Strings
* java-format::                 Java Format Strings
* awk-format::                  awk Format Strings
* object-pascal-format::        Object Pascal Format Strings
* ycp-format::                  YCP Format Strings
* tcl-format::                  Tcl Format Strings
* perl-format::                 Perl Format Strings
* php-format::                  PHP Format Strings
* gcc-internal-format::         GCC internal Format Strings
* qt-format::                   Qt Format Strings

Individual Programming Languages

* C::                           C, C++, Objective C
* sh::                          sh - Shell Script
* bash::                        bash - Bourne-Again Shell Script
* Python::                      Python
* Common Lisp::                 GNU clisp - Common Lisp
* clisp C::                     GNU clisp C sources
* Emacs Lisp::                  Emacs Lisp
* librep::                      librep
* Smalltalk::                   GNU Smalltalk
* Java::                        Java
* gawk::                        GNU awk
* Pascal::                      Pascal - Free Pascal Compiler
* wxWindows::                   wxWindows library
* YCP::                         YCP - YaST2 scripting language
* Tcl::                         Tcl - Tk's scripting language
* Perl::                        Perl
* PHP::                         PHP Hypertext Preprocessor
* Pike::                        Pike
* GCC-source::                  GNU Compiler Collection sources

sh - Shell Script

* Preparing Shell Scripts::     Preparing Shell Scripts for Internationalization
* gettext.sh::                  Contents of `gettext.sh'
* gettext Invocation::          Invoking the `gettext' program
* ngettext Invocation::         Invoking the `ngettext' program
* envsubst Invocation::         Invoking the `envsubst' program
* eval_gettext Invocation::     Invoking the `eval_gettext' function
* eval_ngettext Invocation::    Invoking the `eval_ngettext' function

Perl

* General Problems::            General Problems Parsing Perl Code
* Default Keywords::            Which Keywords Will xgettext Look For?
* Special Keywords::            How to Extract Hash Keys
* Quote-like Expressions::      What are Strings And Quote-like Expressions?
* Interpolation I::             Invalid String Interpolation
* Interpolation II::            Valid String Interpolation
* Parentheses::                 When To Use Parentheses
* Long Lines::                  How To Grok with Long Lines
* Perl Pitfalls::               Bugs, Pitfalls, and Things That Do Not Work

Internationalizable Data

* POT::                         POT - Portable Object Template
* RST::                         Resource String Table
* Glade::                       Glade - GNOME user interface description

Concluding Remarks

* History::                     History of GNU `gettext'
* References::                  Related Readings


File: gettext.info,  Node: Introduction,  Next: Basics,  Prev: Top,  Up: Top

Introduction
************

     This manual is still in _DRAFT_ state.  Some sections are still
     empty, or almost.  We keep merging material from other sources
     (essentially e-mail folders) while the proper integration of this
     material is delayed.

   In this manual, we use _he_ when speaking of the programmer or
maintainer, _she_ when speaking of the translator, and _they_ when
speaking of the installers or end users of the translated program.
This is only a convenience for clarifying the documentation.  It is
_absolutely_ not meant to imply that some roles are more appropriate to
males or females.  Besides, as you might guess, GNU `gettext' is meant
to be useful for people using computers, whatever their sex, race,
religion or nationality!

   This chapter explains the goals sought in the creation of GNU
`gettext' and the free Translation Project.  Then, it explains a few
broad concepts around Native Language Support, and positions message
translation with regard to other aspects of national and cultural
variance, as they apply to to programs.  It also surveys those files
used to convey the translations.  It explains how the various tools
interact in the initial generation of these files, and later, how the
maintenance cycle should usually operate.

   Please send suggestions and corrections to:

     Internet address:
         bug-gnu-gettext@gnu.org

Please include the manual's edition number and update date in your
messages.

* Menu:

* Why::                         The Purpose of GNU `gettext'
* Concepts::                    I18n, L10n, and Such
* Aspects::                     Aspects in Native Language Support
* Files::                       Files Conveying Translations
* Overview::                    Overview of GNU `gettext'


File: gettext.info,  Node: Why,  Next: Concepts,  Prev: Introduction,  Up: Introduction

The Purpose of GNU `gettext'
============================

Usually, programs are written and documented in English, and use
English at execution time to interact with users.  This is true not
only of GNU software, but also of a great deal of commercial and free
software.  Using a common language is quite handy for communication
between developers, maintainers and users from all countries.  On the
other hand, most people are less comfortable with English than with
their own native language, and would prefer to use their mother tongue
for day to day's work, as far as possible.  Many would simply _love_ to
see their computer screen showing a lot less of English, and far more
of their own language.

   However, to many people, this dream might appear so far fetched that
they may believe it is not even worth spending time thinking about it.
They have no confidence at all that the dream might ever become true.
Yet some have not lost hope, and have organized themselves.  The
Translation Project is a formalization of this hope into a workable
structure, which has a good chance to get all of us nearer the
achievement of a truly multi-lingual set of programs.

   GNU `gettext' is an important step for the Translation Project, as
it is an asset on which we may build many other steps.  This package
offers to programmers, translators and even users, a well integrated
set of tools and documentation.  Specifically, the GNU `gettext'
utilities are a set of tools that provides a framework within which
other free packages may produce multi-lingual messages.  These tools
include

   * A set of conventions about how programs should be written to
     support message catalogs.

   * A directory and file naming organization for the message catalogs
     themselves.

   * A runtime library supporting the retrieval of translated messages.

   * A few stand-alone programs to massage in various ways the sets of
     translatable strings, or already translated strings.

   * A special mode for Emacs(1) which helps preparing these sets and
     bringing them up to date.

   GNU `gettext' is designed to minimize the impact of
internationalization on program sources, keeping this impact as small
and hardly noticeable as possible.  Internationalization has better
chances of succeeding if it is very light weighted, or at least, appear
to be so, when looking at program sources.

   The Translation Project also uses the GNU `gettext' distribution as
a vehicle for documenting its structure and methods.  This goes beyond
the strict technicalities of documenting the GNU `gettext' proper.  By
so doing, translators will find in a single place, as far as possible,
all they need to know for properly doing their translating work.  Also,
this supplemental documentation might also help programmers, and even
curious users, in understanding how GNU `gettext' is related to the
remainder of the Translation Project, and consequently, have a glimpse
at the _big picture_.

   ---------- Footnotes ----------

   (1) In this manual, all mentions of Emacs refers to either GNU Emacs
or to XEmacs, which people sometimes call FSF Emacs and Lucid Emacs,
respectively.


File: gettext.info,  Node: Concepts,  Next: Aspects,  Prev: Why,  Up: Introduction

I18n, L10n, and Such
====================

Two long words appear all the time when we discuss support of native
language in programs, and these words have a precise meaning, worth
being explained here, once and for all in this document.  The words are
_internationalization_ and _localization_.  Many people, tired of
writing these long words over and over again, took the habit of writing
"i18n" and "l10n" instead, quoting the first and last letter of each
word, and replacing the run of intermediate letters by a number merely
telling how many such letters there are.  But in this manual, in the
sake of clarity, we will patiently write the names in full, each time...

   By "internationalization", one refers to the operation by which a
program, or a set of programs turned into a package, is made aware of
and able to support multiple languages.  This is a generalization
process, by which the programs are untied from calling only English
strings or other English specific habits, and connected to generic ways
of doing the same, instead.  Program developers may use various
techniques to internationalize their programs.  Some of these have been
standardized.  GNU `gettext' offers one of these standards.  *Note
Programmers::.

   By "localization", one means the operation by which, in a set of
programs already internationalized, one gives the program all needed
information so that it can adapt itself to handle its input and output
in a fashion which is correct for some native language and cultural
habits.  This is a particularisation process, by which generic methods
already implemented in an internationalized program are used in
specific ways.  The programming environment puts several functions to
the programmers disposal which allow this runtime configuration.  The
formal description of specific set of cultural habits for some country,
together with all associated translations targeted to the same native
language, is called the "locale" for this language or country.  Users
achieve localization of programs by setting proper values to special
environment variables, prior to executing those programs, identifying
which locale should be used.

   In fact, locale message support is only one component of the cultural
data that makes up a particular locale.  There are a whole host of
routines and functions provided to aid programmers in developing
internationalized software and which allow them to access the data
stored in a particular locale.  When someone presently refers to a
particular locale, they are obviously referring to the data stored
within that particular locale.  Similarly, if a programmer is referring
to "accessing the locale routines", they are referring to the complete
suite of routines that access all of the locale's information.

   One uses the expression "Native Language Support", or merely NLS,
for speaking of the overall activity or feature encompassing both
internationalization and localization, allowing for multi-lingual
interactions in a program.  In a nutshell, one could say that
internationalization is the operation by which further localizations
are made possible.

   Also, very roughly said, when it comes to multi-lingual messages,
internationalization is usually taken care of by programmers, and
localization is usually taken care of by translators.


File: gettext.info,  Node: Aspects,  Next: Files,  Prev: Concepts,  Up: Introduction

Aspects in Native Language Support
==================================

For a totally multi-lingual distribution, there are many things to
translate beyond output messages.

   * As of today, GNU `gettext' offers a complete toolset for
     translating messages output by C programs.  Perl scripts and shell
     scripts will also need to be translated.  Even if there are today
     some hooks by which this can be done, these hooks are not
     integrated as well as they should be.

   * Some programs, like `autoconf' or `bison', are able to produce
     other programs (or scripts).  Even if the generating programs
     themselves are internationalized, the generated programs they
     produce may need internationalization on their own, and this
     indirect internationalization could be automated right from the
     generating program.  In fact, quite usually, generating and
     generated programs could be internationalized independently, as
     the effort needed is fairly orthogonal.

   * A few programs include textual tables which might need translation
     themselves, independently of the strings contained in the program
     itself.  For example, RFC 1345 gives an English description for
     each character which the `recode' program is able to reconstruct
     at execution.  Since these descriptions are extracted from the RFC
     by mechanical means, translating them properly would require a
     prior translation of the RFC itself.

   * Almost all programs accept options, which are often worded out so
     to be descriptive for the English readers; one might want to
     consider offering translated versions for program options as well.

   * Many programs read, interpret, compile, or are somewhat driven by
     input files which are texts containing keywords, identifiers, or
     replies which are inherently translatable.  For example, one may
     want `gcc' to allow diacriticized characters in identifiers or use
     translated keywords; `rm -i' might accept something else than `y'
     or `n' for replies, etc.  Even if the program will eventually make
     most of its output in the foreign languages, one has to decide
     whether the input syntax, option values, etc., are to be localized
     or not.

   * The manual accompanying a package, as well as all documentation
     files in the distribution, could surely be translated, too.
     Translating a manual, with the intent of later keeping up with
     updates, is a major undertaking in itself, generally.


   As we already stressed, translation is only one aspect of locales.
Other internationalization aspects are system services and are handled
in GNU `libc'.  There are many attributes that are needed to define a
country's cultural conventions.  These attributes include beside the
country's native language, the formatting of the date and time, the
representation of numbers, the symbols for currency, etc.  These local
"rules" are termed the country's locale.  The locale represents the
knowledge needed to support the country's native attributes.

   There are a few major areas which may vary between countries and
hence, define what a locale must describe.  The following list helps
putting multi-lingual messages into the proper context of other tasks
related to locales.  See the GNU `libc' manual for details.

_Characters and Codesets_
     The codeset most commonly used through out the USA and most English
     speaking parts of the world is the ASCII codeset.  However, there
     are many characters needed by various locales that are not found
     within this codeset.  The 8-bit ISO 8859-1 code set has most of
     the special characters needed to handle the major European
     languages.  However, in many cases, the ISO 8859-1 font is not
     adequate: it doesn't even handle the major European currency.
     Hence each locale will need to specify which codeset they need to
     use and will need to have the appropriate character handling
     routines to cope with the codeset.

_Currency_
     The symbols used vary from country to country as does the position
     used by the symbol.  Software needs to be able to transparently
     display currency figures in the native mode for each locale.

_Dates_
     The format of date varies between locales.  For example, Christmas
     day in 1994 is written as 12/25/94 in the USA and as 25/12/94 in
     Australia.  Other countries might use ISO 8061 dates, etc.

     Time of the day may be noted as HH:MM, HH.MM, or otherwise.  Some
     locales require time to be specified in 24-hour mode rather than
     as AM or PM.  Further, the nature and yearly extent of the
     Daylight Saving correction vary widely between countries.

_Numbers_
     Numbers can be represented differently in different locales.  For
     example, the following numbers are all written correctly for their
     respective locales:

          12,345.67       English
          12.345,67       German
           12345,67       French
          1,2345.67       Asia

     Some programs could go further and use different unit systems, like
     English units or Metric units, or even take into account variants
     about how numbers are spelled in full.

_Messages_
     The most obvious area is the language support within a locale.
     This is where GNU `gettext' provides the means for developers and
     users to easily change the language that the software uses to
     communicate to the user.


   Components of locale outside of message handling are standardized in
the ISO C standard and the SUSV2 specification.  GNU `libc' fully
implements this, and most other modern systems provide a more or less
reasonable support for at least some of the missing components.


File: gettext.info,  Node: Files,  Next: Overview,  Prev: Aspects,  Up: Introduction

Files Conveying Translations
============================

The letters PO in `.po' files means Portable Object, to distinguish it
from `.mo' files, where MO stands for Machine Object.  This paradigm,
as well as the PO file format, is inspired by the NLS standard
developed by Uniforum, and first implemented by Sun in their Solaris
system.

   PO files are meant to be read and edited by humans, and associate
each original, translatable string of a given package with its
translation in a particular target language.  A single PO file is
dedicated to a single target language.  If a package supports many
languages, there is one such PO file per language supported, and each
package has its own set of PO files.  These PO files are best created by
the `xgettext' program, and later updated or refreshed through the
`msgmerge' program.  Program `xgettext' extracts all marked messages
from a set of C files and initializes a PO file with empty
translations.  Program `msgmerge' takes care of adjusting PO files
between releases of the corresponding sources, commenting obsolete
entries, initializing new ones, and updating all source line
references.  Files ending with `.pot' are kind of base translation
files found in distributions, in PO file format.

   MO files are meant to be read by programs, and are binary in nature.
A few systems already offer tools for creating and handling MO files as
part of the Native Language Support coming with the system, but the
format of these MO files is often different from system to system, and
non-portable.  The tools already provided with these systems don't
support all the features of GNU `gettext'.  Therefore GNU `gettext'
uses its own format for MO files.  Files ending with `.gmo' are really
MO files, when it is known that these files use the GNU format.


File: gettext.info,  Node: Overview,  Prev: Files,  Up: Introduction

Overview of GNU `gettext'
=========================

The following diagram summarizes the relation between the files handled
by GNU `gettext' and the tools acting on these files.  It is followed
by somewhat detailed explanations, which you should read while keeping
an eye on the diagram.  Having a clear understanding of these
interrelations will surely help programmers, translators and
maintainers.

     Original C Sources ---> PO mode ---> Marked C Sources ---.
                                                              |
                   .---------<--- GNU gettext Library         |
     .--- make <---+                                          |
     |             `---------<--------------------+-----------'
     |                                            |
     |   .-----<--- PACKAGE.pot <--- xgettext <---'   .---<--- PO Compendium
     |   |                                            |             ^
     |   |                                            `---.         |
     |   `---.                                            +---> PO mode ---.
     |       +----> msgmerge ------> LANG.po ---->--------'                |
     |   .---'                                                             |
     |   |                                                                 |
     |   `-------------<---------------.                                   |
     |                                 +--- New LANG.po <------------------'
     |   .--- LANG.gmo <--- msgfmt <---'
     |   |
     |   `---> install ---> /.../LANG/PACKAGE.mo ---.
     |                                              +---> "Hello world!"
     `-------> install ---> /.../bin/PROGRAM -------'

   The indication `PO mode' appears in two places in this picture, and
you may safely read it as merely meaning "hand editing", using any
editor of your choice, really.  However, for those of you being the
lucky users of Emacs, PO mode has been specifically created for
providing a cozy environment for editing or modifying PO files.  While
editing a PO file, PO mode allows for the easy browsing of auxiliary
and compendium PO files, as well as for following references into the
set of C program sources from which PO files have been derived.  It has
a few special features, among which are the interactive marking of
program strings as translatable, and the validation of PO files with
easy repositioning to PO file lines showing errors.

   As a programmer, the first step to bringing GNU `gettext' into your
package is identifying, right in the C sources, those strings which are
meant to be translatable, and those which are untranslatable.  This
tedious job can be done a little more comfortably using emacs PO mode,
but you can use any means familiar to you for modifying your C sources.
Beside this some other simple, standard changes are needed to properly
initialize the translation library.  *Note Sources::, for more
information about all this.

   For newly written software the strings of course can and should be
marked while writing it.  The `gettext' approach makes this very easy.
Simply put the following lines at the beginning of each file or in a
central header file:

     #define _(String) (String)
     #define N_(String) String
     #define textdomain(Domain)
     #define bindtextdomain(Package, Directory)

Doing this allows you to prepare the sources for internationalization.
Later when you feel ready for the step to use the `gettext' library
simply replace these definitions by the following:

     #include <libintl.h>
     #define _(String) gettext (String)
     #define gettext_noop(String) String
     #define N_(String) gettext_noop (String)

and link against `libintl.a' or `libintl.so'.  Note that on GNU
systems, you don't need to link with `libintl' because the `gettext'
library functions are already contained in GNU libc.  That is all you
have to change.

   Once the C sources have been modified, the `xgettext' program is
used to find and extract all translatable strings, and create a PO
template file out of all these.  This `PACKAGE.pot' file contains all
original program strings.  It has sets of pointers to exactly where in
C sources each string is used.  All translations are set to empty.  The
letter `t' in `.pot' marks this as a Template PO file, not yet oriented
towards any particular language.  *Note xgettext Invocation::, for more
details about how one calls the `xgettext' program.  If you are
_really_ lazy, you might be interested at working a lot more right
away, and preparing the whole distribution setup (*note Maintainers::).
By doing so, you spare yourself typing the `xgettext' command, as
`make' should now generate the proper things automatically for you!

   The first time through, there is no `LANG.po' yet, so the `msgmerge'
step may be skipped and replaced by a mere copy of `PACKAGE.pot' to
`LANG.po', where LANG represents the target language.  See *Note
Creating:: for details.

   Then comes the initial translation of messages.  Translation in
itself is a whole matter, still exclusively meant for humans, and whose
complexity far overwhelms the level of this manual.  Nevertheless, a
few hints are given in some other chapter of this manual (*note
Translators::).  You will also find there indications about how to
contact translating teams, or becoming part of them, for sharing your
translating concerns with others who target the same native language.

   While adding the translated messages into the `LANG.po' PO file, if
you do not have Emacs handy, you are on your own for ensuring that your
efforts fully respect the PO file format, and quoting conventions
(*note PO Files::).  This is surely not an impossible task, as this is
the way many people have handled PO files already for Uniforum or
Solaris.  On the other hand, by using PO mode in Emacs, most details of
PO file format are taken care of for you, but you have to acquire some
familiarity with PO mode itself.  Besides main PO mode commands (*note
Main PO Commands::), you should know how to move between entries (*note
Entry Positioning::), and how to handle untranslated entries (*note
Untranslated Entries::).

   If some common translations have already been saved into a compendium
PO file, translators may use PO mode for initializing untranslated
entries from the compendium, and also save selected translations into
the compendium, updating it (*note Compendium::).  Compendium files are
meant to be exchanged between members of a given translation team.

   Programs, or packages of programs, are dynamic in nature: users write
bug reports and suggestion for improvements, maintainers react by
modifying programs in various ways.  The fact that a package has
already been internationalized should not make maintainers shy of
adding new strings, or modifying strings already translated.  They just
do their job the best they can.  For the Translation Project to work
smoothly, it is important that maintainers do not carry translation
concerns on their already loaded shoulders, and that translators be
kept as free as possible of programming concerns.

   The only concern maintainers should have is carefully marking new
strings as translatable, when they should be, and do not otherwise
worry about them being translated, as this will come in proper time.
Consequently, when programs and their strings are adjusted in various
ways by maintainers, and for matters usually unrelated to translation,
`xgettext' would construct `PACKAGE.pot' files which are evolving over
time, so the translations carried by `LANG.po' are slowly fading out of
date.

   It is important for translators (and even maintainers) to understand
that package translation is a continuous process in the lifetime of a
package, and not something which is done once and for all at the start.
After an initial burst of translation activity for a given package,
interventions are needed once in a while, because here and there,
translated entries become obsolete, and new untranslated entries
appear, needing translation.

   The `msgmerge' program has the purpose of refreshing an already
existing `LANG.po' file, by comparing it with a newer `PACKAGE.pot'
template file, extracted by `xgettext' out of recent C sources.  The
refreshing operation adjusts all references to C source locations for
strings, since these strings move as programs are modified.  Also,
`msgmerge' comments out as obsolete, in `LANG.po', those already
translated entries which are no longer used in the program sources
(*note Obsolete Entries::).  It finally discovers new strings and
inserts them in the resulting PO file as untranslated entries (*note
Untranslated Entries::).  *Note msgmerge Invocation::, for more
information about what `msgmerge' really does.

   Whatever route or means taken, the goal is to obtain an updated
`LANG.po' file offering translations for all strings.

   The temporal mobility, or fluidity of PO files, is an integral part
of the translation game, and should be well understood, and accepted.
People resisting it will have a hard time participating in the
Translation Project, or will give a hard time to other participants!  In
particular, maintainers should relax and include all available official
PO files in their distributions, even if these have not recently been
updated, without exerting pressure on the translator teams to get the
job done.  The pressure should rather come from the community of users
speaking a particular language, and maintainers should consider
themselves fairly relieved of any concern about the adequacy of
translation files.  On the other hand, translators should reasonably
try updating the PO files they are responsible for, while the package
is undergoing pretest, prior to an official distribution.

   Once the PO file is complete and dependable, the `msgfmt' program is
used for turning the PO file into a machine-oriented format, which may
yield efficient retrieval of translations by the programs of the
package, whenever needed at runtime (*note MO Files::).  *Note msgfmt
Invocation::, for more information about all modes of execution for the
`msgfmt' program.

   Finally, the modified and marked C sources are compiled and linked
with the GNU `gettext' library, usually through the operation of
`make', given a suitable `Makefile' exists for the project, and the
resulting executable is installed somewhere users will find it.  The MO
files themselves should also be properly installed.  Given the
appropriate environment variables are set (*note End Users::), the
program should localize itself automatically, whenever it executes.

   The remainder of this manual has the purpose of explaining in depth
the various steps outlined above.


File: gettext.info,  Node: Basics,  Next: Sources,  Prev: Introduction,  Up: Top

PO Files and PO Mode Basics
***************************

The GNU `gettext' toolset helps programmers and translators at
producing, updating and using translation files, mainly those PO files
which are textual, editable files.  This chapter stresses the format of
PO files, and contains a PO mode starter.  PO mode description is
spread throughout this manual instead of being concentrated in one
place.  Here we present only the basics of PO mode.

* Menu:

* Installation::                Completing GNU `gettext' Installation
* PO Files::                    The Format of PO Files
* Main PO Commands::            Main Commands
* Entry Positioning::           Entry Positioning
* Normalizing::                 Normalizing Strings in Entries


File: gettext.info,  Node: Installation,  Next: PO Files,  Prev: Basics,  Up: Basics

Completing GNU `gettext' Installation
=====================================

Once you have received, unpacked, configured and compiled the GNU
`gettext' distribution, the `make install' command puts in place the
programs `xgettext', `msgfmt', `gettext', and `msgmerge', as well as
their available message catalogs.  To top off a comfortable
installation, you might also want to make the PO mode available to your
Emacs users.

   During the installation of the PO mode, you might want to modify your
file `.emacs', once and for all, so it contains a few lines looking
like:

     (setq auto-mode-alist
           (cons '("\\.po\\'\\|\\.po\\." . po-mode) auto-mode-alist))
     (autoload 'po-mode "po-mode" "Major mode for translators to edit PO files" t)

   Later, whenever you edit some `.po' file, or any file having the
string `.po.' within its name, Emacs loads `po-mode.elc' (or
`po-mode.el') as needed, and automatically activates PO mode commands
for the associated buffer.  The string _PO_ appears in the mode line
for any buffer for which PO mode is active.  Many PO files may be
active at once in a single Emacs session.

   If you are using Emacs version 20 or newer, and have already
installed the appropriate international fonts on your system, you may
also tell Emacs how to determine automatically the coding system of
every PO file.  This will often (but not always) cause the necessary
fonts to be loaded and used for displaying the translations on your
Emacs screen.  For this to happen, add the lines:

     (modify-coding-system-alist 'file "\\.po\\'\\|\\.po\\."
                                 'po-find-file-coding-system)
     (autoload 'po-find-file-coding-system "po-mode")

to your `.emacs' file.  If, with this, you still see boxes instead of
international characters, try a different font set (via Shift Mouse
button 1).


File: gettext.info,  Node: PO Files,  Next: Main PO Commands,  Prev: Installation,  Up: Basics

The Format of PO Files
======================

A PO file is made up of many entries, each entry holding the relation
between an original untranslated string and its corresponding
translation.  All entries in a given PO file usually pertain to a
single project, and all translations are expressed in a single target
language.  One PO file "entry" has the following schematic structure:

     WHITE-SPACE
     #  TRANSLATOR-COMMENTS
     #. AUTOMATIC-COMMENTS
     #: REFERENCE...
     #, FLAG...
     msgid UNTRANSLATED-STRING
     msgstr TRANSLATED-STRING

   The general structure of a PO file should be well understood by the
translator.  When using PO mode, very little has to be known about the
format details, as PO mode takes care of them for her.

   A simple entry can look like this:

     #: lib/error.c:116
     msgid "Unknown system error"
     msgstr "Error desconegut del sistema"

   Entries begin with some optional white space.  Usually, when
generated through GNU `gettext' tools, there is exactly one blank line
between entries.  Then comments follow, on lines all starting with the
character `#'.  There are two kinds of comments: those which have some
white space immediately following the `#', which comments are created
and maintained exclusively by the translator, and those which have some
non-white character just after the `#', which comments are created and
maintained automatically by GNU `gettext' tools.  All comments, of
either kind, are optional.

   After white space and comments, entries show two strings, namely
first the untranslated string as it appears in the original program
sources, and then, the translation of this string.  The original string
is introduced by the keyword `msgid', and the translation, by `msgstr'.
The two strings, untranslated and translated, are quoted in various
ways in the PO file, using `"' delimiters and `\' escapes, but the
translator does not really have to pay attention to the precise quoting
format, as PO mode fully takes care of quoting for her.

   The `msgid' strings, as well as automatic comments, are produced and
managed by other GNU `gettext' tools, and PO mode does not provide
means for the translator to alter these.  The most she can do is merely
deleting them, and only by deleting the whole entry.  On the other
hand, the `msgstr' string, as well as translator comments, are really
meant for the translator, and PO mode gives her the full control she
needs.

   The comment lines beginning with `#,' are special because they are
not completely ignored by the programs as comments generally are.  The
comma separated list of FLAGs is used by the `msgfmt' program to give
the user some better diagnostic messages.  Currently there are two
forms of flags defined:

`fuzzy'
     This flag can be generated by the `msgmerge' program or it can be
     inserted by the translator herself.  It shows that the `msgstr'
     string might not be a correct translation (anymore).  Only the
     translator can judge if the translation requires further
     modification, or is acceptable as is.  Once satisfied with the
     translation, she then removes this `fuzzy' attribute.  The
     `msgmerge' program inserts this when it combined the `msgid' and
     `msgstr' entries after fuzzy search only.  *Note Fuzzy Entries::.

`c-format'
`no-c-format'
     These flags should not be added by a human.  Instead only the
     `xgettext' program adds them.  In an automated PO file processing
     system as proposed here the user changes would be thrown away
     again as soon as the `xgettext' program generates a new template
     file.

     The `c-format' flag tells that the untranslated string and the
     translation are supposed to be C format strings.  The `no-c-format'
     flag tells that they are not C format strings, even though the
     untranslated string happens to look like a C format string (with
     `%' directives).

     In case the `c-format' flag is given for a string the `msgfmt'
     does some more tests to check to validity of the translation.
     *Note msgfmt Invocation::, *Note c-format Flag:: and *Note
     c-format::.

`objc-format'
`no-objc-format'
     Likewise for Objective C, see *Note objc-format::.

`sh-format'
`no-sh-format'
     Likewise for Shell, see *Note sh-format::.

`python-format'
`no-python-format'
     Likewise for Python, see *Note python-format::.

`lisp-format'
`no-lisp-format'
     Likewise for Lisp, see *Note lisp-format::.

`elisp-format'
`no-elisp-format'
     Likewise for Emacs Lisp, see *Note elisp-format::.

`librep-format'
`no-librep-format'
     Likewise for librep, see *Note librep-format::.

`smalltalk-format'
`no-smalltalk-format'
     Likewise for Smalltalk, see *Note smalltalk-format::.

`java-format'
`no-java-format'
     Likewise for Java, see *Note java-format::.

`awk-format'
`no-awk-format'
     Likewise for awk, see *Note awk-format::.

`object-pascal-format'
`no-object-pascal-format'
     Likewise for Object Pascal, see *Note object-pascal-format::.

`ycp-format'
`no-ycp-format'
     Likewise for YCP, see *Note ycp-format::.

`tcl-format'
`no-tcl-format'
     Likewise for Tcl, see *Note tcl-format::.

`perl-format'
`no-perl-format'
     Likewise for Perl, see *Note perl-format::.

`perl-brace-format'
`no-perl-brace-format'
     Likewise for Perl brace, see *Note perl-format::.

`php-format'
`no-php-format'
     Likewise for PHP, see *Note php-format::.

`gcc-internal-format'
`no-gcc-internal-format'
     Likewise for the GCC sources, see *Note gcc-internal-format::.

`qt-format'
`no-qt-format'
     Likewise for Qt, see *Note qt-format::.


   A different kind of entries is used for translations which involve
plural forms.

     WHITE-SPACE
     #  TRANSLATOR-COMMENTS
     #. AUTOMATIC-COMMENTS
     #: REFERENCE...
     #, FLAG...
     msgid UNTRANSLATED-STRING-SINGULAR
     msgid_plural UNTRANSLATED-STRING-PLURAL
     msgstr[0] TRANSLATED-STRING-CASE-0
     ...
     msgstr[N] TRANSLATED-STRING-CASE-N

   Such an entry can look like this:

     #: src/msgcmp.c:338 src/po-lex.c:699
     #, c-format
     msgid "found %d fatal error"
     msgid_plural "found %d fatal errors"
     msgstr[0] "s'ha trobat %d error fatal"
     msgstr[1] "s'han trobat %d errors fatals"

   It happens that some lines, usually whitespace or comments, follow
the very last entry of a PO file.  Such lines are not part of any entry,
and PO mode is unable to take action on those lines.  By using the PO
mode function `M-x po-normalize', the translator may get rid of those
spurious lines.  *Note Normalizing::.

   The remainder of this section may be safely skipped by those using
PO mode, yet it may be interesting for everybody to have a better idea
of the precise format of a PO file.  On the other hand, those not
having Emacs handy should carefully continue reading on.

   Each of UNTRANSLATED-STRING and TRANSLATED-STRING respects the C
syntax for a character string, including the surrounding quotes and
embedded backslashed escape sequences.  When the time comes to write
multi-line strings, one should not use escaped newlines.  Instead, a
closing quote should follow the last character on the line to be
continued, and an opening quote should resume the string at the
beginning of the following PO file line.  For example:

     msgid ""
     "Here is an example of how one might continue a very long string\n"
     "for the common case the string represents multi-line output.\n"

In this example, the empty string is used on the first line, to allow
better alignment of the `H' from the word `Here' over the `f' from the
word `for'.  In this example, the `msgid' keyword is followed by three
strings, which are meant to be concatenated.  Concatenating the empty
string does not change the resulting overall string, but it is a way
for us to comply with the necessity of `msgid' to be followed by a
string on the same line, while keeping the multi-line presentation
left-justified, as we find this to be a cleaner disposition.  The empty
string could have been omitted, but only if the string starting with
`Here' was promoted on the first line, right after `msgid'.(1) It was
not really necessary either to switch between the two last quoted
strings immediately after the newline `\n', the switch could have
occurred after _any_ other character, we just did it this way because
it is neater.

   One should carefully distinguish between end of lines marked as `\n'
_inside_ quotes, which are part of the represented string, and end of
lines in the PO file itself, outside string quotes, which have no
incidence on the represented string.

   Outside strings, white lines and comments may be used freely.
Comments start at the beginning of a line with `#' and extend until the
end of the PO file line.  Comments written by translators should have
the initial `#' immediately followed by some white space.  If the `#'
is not immediately followed by white space, this comment is most likely
generated and managed by specialized GNU tools, and might disappear or
be replaced unexpectedly when the PO file is given to `msgmerge'.

   ---------- Footnotes ----------

   (1) This limitation is not imposed by GNU `gettext', but is for
compatibility with the `msgfmt' implementation on Solaris.


File: gettext.info,  Node: Main PO Commands,  Next: Entry Positioning,  Prev: PO Files,  Up: Basics

Main PO mode Commands
=====================

After setting up Emacs with something similar to the lines in *Note
Installation::, PO mode is activated for a window when Emacs finds a PO
file in that window.  This puts the window read-only and establishes a
po-mode-map, which is a genuine Emacs mode, in a way that is not derived
from text mode in any way.  Functions found on `po-mode-hook', if any,
will be executed.

   When PO mode is active in a window, the letters `PO' appear in the
mode line for that window.  The mode line also displays how many
entries of each kind are held in the PO file.  For example, the string
`132t+3f+10u+2o' would tell the translator that the PO mode contains
132 translated entries (*note Translated Entries::, 3 fuzzy entries
(*note Fuzzy Entries::), 10 untranslated entries (*note Untranslated
Entries::) and 2 obsolete entries (*note Obsolete Entries::).
Zero-coefficients items are not shown.  So, in this example, if the
fuzzy entries were unfuzzied, the untranslated entries were translated
and the obsolete entries were deleted, the mode line would merely
display `145t' for the counters.

   The main PO commands are those which do not fit into the other
categories of subsequent sections.  These allow for quitting PO mode or
for managing windows in special ways.

`_'
     Undo last modification to the PO file (`po-undo').

`Q'
     Quit processing and save the PO file (`po-quit').

`q'
     Quit processing, possibly after confirmation
     (`po-confirm-and-quit').

`0'
     Temporary leave the PO file window (`po-other-window').

`?'
`h'
     Show help about PO mode (`po-help').

`='
     Give some PO file statistics (`po-statistics').

`V'
     Batch validate the format of the whole PO file (`po-validate').


   The command `_' (`po-undo') interfaces to the Emacs _undo_ facility.
*Note Undoing Changes: (emacs)Undo.  Each time `U' is typed,
modifications which the translator did to the PO file are undone a
little more.  For the purpose of undoing, each PO mode command is
atomic.  This is especially true for the `<RET>' command: the whole
edition made by using a single use of this command is undone at once,
even if the edition itself implied several actions.  However, while in
the editing window, one can undo the edition work quite parsimoniously.

   The commands `Q' (`po-quit') and `q' (`po-confirm-and-quit') are
used when the translator is done with the PO file.  The former is a bit
less verbose than the latter.  If the file has been modified, it is
saved to disk first.  In both cases, and prior to all this, the
commands check if any untranslated messages remain in the PO file and,
if so, the translator is asked if she really wants to leave off working
with this PO file.  This is the preferred way of getting rid of an
Emacs PO file buffer.  Merely killing it through the usual command
`C-x k' (`kill-buffer') is not the tidiest way to proceed.

   The command `0' (`po-other-window') is another, softer way, to leave
PO mode, temporarily.  It just moves the cursor to some other Emacs
window, and pops one if necessary.  For example, if the translator just
got PO mode to show some source context in some other, she might
discover some apparent bug in the program source that needs correction.
This command allows the translator to change sex, become a programmer,
and have the cursor right into the window containing the program she
(or rather _he_) wants to modify.  By later getting the cursor back in
the PO file window, or by asking Emacs to edit this file once again, PO
mode is then recovered.

   The command `h' (`po-help') displays a summary of all available PO
mode commands.  The translator should then type any character to resume
normal PO mode operations.  The command `?' has the same effect as `h'.

   The command `=' (`po-statistics') computes the total number of
entries in the PO file, the ordinal of the current entry (counted from
1), the number of untranslated entries, the number of obsolete entries,
and displays all these numbers.

   The command `V' (`po-validate') launches `msgfmt' in checking and
verbose mode over the current PO file.  This command first offers to
save the current PO file on disk.  The `msgfmt' tool, from GNU
`gettext', has the purpose of creating a MO file out of a PO file, and
PO mode uses the features of this program for checking the overall
format of a PO file, as well as all individual entries.

   The program `msgfmt' runs asynchronously with Emacs, so the
translator regains control immediately while her PO file is being
studied.  Error output is collected in the Emacs `*compilation*' buffer,
displayed in another window.  The regular Emacs command `C-x`'
(`next-error'), as well as other usual compile commands, allow the
translator to reposition quickly to the offending parts of the PO file.
Once the cursor is on the line in error, the translator may decide on
any PO mode action which would help correcting the error.


File: gettext.info,  Node: Entry Positioning,  Next: Normalizing,  Prev: Main PO Commands,  Up: Basics

Entry Positioning
=================

The cursor in a PO file window is almost always part of an entry.  The
only exceptions are the special case when the cursor is after the last
entry in the file, or when the PO file is empty.  The entry where the
cursor is found to be is said to be the current entry.  Many PO mode
commands operate on the current entry, so moving the cursor does more
than allowing the translator to browse the PO file, this also selects
on which entry commands operate.

   Some PO mode commands alter the position of the cursor in a
specialized way.  A few of those special purpose positioning are
described here, the others are described in following sections (for a
complete list try `C-h m'):

`.'
     Redisplay the current entry (`po-current-entry').

`n'
     Select the entry after the current one (`po-next-entry').

`p'
     Select the entry before the current one (`po-previous-entry').

`<'
     Select the first entry in the PO file (`po-first-entry').

`>'
     Select the last entry in the PO file (`po-last-entry').

`m'
     Record the location of the current entry for later use
     (`po-push-location').

`r'
     Return to a previously saved entry location (`po-pop-location').

`x'
     Exchange the current entry location with the previously saved one
     (`po-exchange-location').


   Any Emacs command able to reposition the cursor may be used to
select the current entry in PO mode, including commands which move by
characters, lines, paragraphs, screens or pages, and search commands.
However, there is a kind of standard way to display the current entry
in PO mode, which usual Emacs commands moving the cursor do not
especially try to enforce.  The command `.' (`po-current-entry') has
the sole purpose of redisplaying the current entry properly, after the
current entry has been changed by means external to PO mode, or the
Emacs screen otherwise altered.

   It is yet to be decided if PO mode helps the translator, or otherwise
irritates her, by forcing a rigid window disposition while she is doing
her work.  We originally had quite precise ideas about how windows
should behave, but on the other hand, anyone used to Emacs is often
happy to keep full control.  Maybe a fixed window disposition might be
offered as a PO mode option that the translator might activate or
deactivate at will, so it could be offered on an experimental basis.
If nobody feels a real need for using it, or a compulsion for writing
it, we should drop this whole idea.  The incentive for doing it should
come from translators rather than programmers, as opinions from an
experienced translator are surely more worth to me than opinions from
programmers _thinking_ about how _others_ should do translation.

   The commands `n' (`po-next-entry') and `p' (`po-previous-entry')
move the cursor the entry following, or preceding, the current one.  If
`n' is given while the cursor is on the last entry of the PO file, or
if `p' is given while the cursor is on the first entry, no move is done.

   The commands `<' (`po-first-entry') and `>' (`po-last-entry') move
the cursor to the first entry, or last entry, of the PO file.  When the
cursor is located past the last entry in a PO file, most PO mode
commands will return an error saying `After last entry'.  Moreover, the
commands `<' and `>' have the special property of being able to work
even when the cursor is not into some PO file entry, and one may use
them for nicely correcting this situation.  But even these commands
will fail on a truly empty PO file.  There are development plans for
the PO mode for it to interactively fill an empty PO file from sources.
*Note Marking::.

   The translator may decide, before working at the translation of a
particular entry, that she needs to browse the remainder of the PO
file, maybe for finding the terminology or phraseology used in related
entries.  She can of course use the standard Emacs idioms for saving
the current cursor location in some register, and use that register for
getting back, or else, use the location ring.

   PO mode offers another approach, by which cursor locations may be
saved onto a special stack.  The command `m' (`po-push-location')
merely adds the location of current entry to the stack, pushing the
already saved locations under the new one.  The command `r'
(`po-pop-location') consumes the top stack element and repositions the
cursor to the entry associated with that top element.  This position is
then lost, for the next `r' will move the cursor to the previously
saved location, and so on until no locations remain on the stack.

   If the translator wants the position to be kept on the location
stack, maybe for taking a look at the entry associated with the top
element, then go elsewhere with the intent of getting back later, she
ought to use `m' immediately after `r'.

   The command `x' (`po-exchange-location') simultaneously repositions
the cursor to the entry associated with the top element of the stack of
saved locations, and replaces that top element with the location of the
current entry before the move.  Consequently, repeating the `x' command
toggles alternatively between two entries.  For achieving this, the
translator will position the cursor on the first entry, use `m', then
position to the second entry, and merely use `x' for making the switch.


File: gettext.info,  Node: Normalizing,  Prev: Entry Positioning,  Up: Basics

Normalizing Strings in Entries
==============================

There are many different ways for encoding a particular string into a
PO file entry, because there are so many different ways to split and
quote multi-line strings, and even, to represent special characters by
backslashed escaped sequences.  Some features of PO mode rely on the
ability for PO mode to scan an already existing PO file for a
particular string encoded into the `msgid' field of some entry.  Even
if PO mode has internally all the built-in machinery for implementing
this recognition easily, doing it fast is technically difficult.  To
facilitate a solution to this efficiency problem, we decided on a
canonical representation for strings.

   A conventional representation of strings in a PO file is currently
under discussion, and PO mode experiments with a canonical
representation.  Having both `xgettext' and PO mode converging towards
a uniform way of representing equivalent strings would be useful, as
the internal normalization needed by PO mode could be automatically
satisfied when using `xgettext' from GNU `gettext'.  An explicit PO
mode normalization should then be only necessary for PO files imported
from elsewhere, or for when the convention itself evolves.

   So, for achieving normalization of at least the strings of a given
PO file needing a canonical representation, the following PO mode
command is available:

`M-x po-normalize'
     Tidy the whole PO file by making entries more uniform.


   The special command `M-x po-normalize', which has no associated
keys, revises all entries, ensuring that strings of both original and
translated entries use uniform internal quoting in the PO file.  It
also removes any crumb after the last entry.  This command may be
useful for PO files freshly imported from elsewhere, or if we ever
improve on the canonical quoting format we use.  This canonical format
is not only meant for getting cleaner PO files, but also for greatly
speeding up `msgid' string lookup for some other PO mode commands.

   `M-x po-normalize' presently makes three passes over the entries.
The first implements heuristics for converting PO files for GNU
`gettext' 0.6 and earlier, in which `msgid' and `msgstr' fields were
using K&R style C string syntax for multi-line strings.  These
heuristics may fail for comments not related to obsolete entries and
ending with a backslash; they also depend on subsequent passes for
finalizing the proper commenting of continued lines for obsolete
entries.  This first pass might disappear once all oldish PO files
would have been adjusted.  The second and third pass normalize all
`msgid' and `msgstr' strings respectively.  They also clean out those
trailing backslashes used by XView's `msgfmt' for continued lines.

   Having such an explicit normalizing command allows for importing PO
files from other sources, but also eases the evolution of the current
convention, evolution driven mostly by aesthetic concerns, as of now.
It is easy to make suggested adjustments at a later time, as the
normalizing command and eventually, other GNU `gettext' tools should
greatly automate conformance.  A description of the canonical string
format is given below, for the particular benefit of those not having
Emacs handy, and who would nevertheless want to handcraft their PO
files in nice ways.

   Right now, in PO mode, strings are single line or multi-line.  A
string goes multi-line if and only if it has _embedded_ newlines, that
is, if it matches `[^\n]\n+[^\n]'.  So, we would have:

     msgstr "\n\nHello, world!\n\n\n"

   but, replacing the space by a newline, this becomes:

     msgstr ""
     "\n"
     "\n"
     "Hello,\n"
     "world!\n"
     "\n"
     "\n"

   We are deliberately using a caricatural example, here, to make the
point clearer.  Usually, multi-lines are not that bad looking.  It is
probable that we will implement the following suggestion.  We might
lump together all initial newlines into the empty string, and also all
newlines introducing empty lines (that is, for N > 1, the N-1'th last
newlines would go together on a separate string), so making the
previous example appear:

     msgstr "\n\n"
     "Hello,\n"
     "world!\n"
     "\n\n"

   There are a few yet undecided little points about string
normalization, to be documented in this manual, once these questions
settle.


File: gettext.info,  Node: Sources,  Next: Template,  Prev: Basics,  Up: Top

Preparing Program Sources
*************************

For the programmer, changes to the C source code fall into three
categories.  First, you have to make the localization functions known
to all modules needing message translation.  Second, you should
properly trigger the operation of GNU `gettext' when the program
initializes, usually from the `main' function.  Last, you should
identify and especially mark all constant strings in your program
needing translation.

   Presuming that your set of programs, or package, has been adjusted
so all needed GNU `gettext' files are available, and your `Makefile'
files are adjusted (*note Maintainers::), each C module having
translated C strings should contain the line:

     #include <libintl.h>

   Similarly, each C module containing `printf()'/`fprintf()'/...
calls with a format string that could be a translated C string (even if
the C string comes from a different C module) should contain the line:

     #include <libintl.h>

   The remaining changes to your C sources are discussed in the further
sections of this chapter.

* Menu:

* Triggering::                  Triggering `gettext' Operations
* Preparing Strings::           Preparing Translatable Strings
* Mark Keywords::               How Marks Appear in Sources
* Marking::                     Marking Translatable Strings
* c-format Flag::               Telling something about the following string
* Special cases::               Special Cases of Translatable Strings
* Names::                       Marking Proper Names for Translation


File: gettext.info,  Node: Triggering,  Next: Preparing Strings,  Prev: Sources,  Up: Sources

Triggering `gettext' Operations
===============================

The initialization of locale data should be done with more or less the
same code in every program, as demonstrated below:

     int
     main (argc, argv)
          int argc;
          char argv;
     {
       ...
       setlocale (LC_ALL, "");
       bindtextdomain (PACKAGE, LOCALEDIR);
       textdomain (PACKAGE);
       ...
     }

   PACKAGE and LOCALEDIR should be provided either by `config.h' or by
the Makefile.  For now consult the `gettext' or `hello' sources for
more information.

   The use of `LC_ALL' might not be appropriate for you.  `LC_ALL'
includes all locale categories and especially `LC_CTYPE'.  This later
category is responsible for determining character classes with the
`isalnum' etc. functions from `ctype.h' which could especially for
programs, which process some kind of input language, be wrong.  For
example this would mean that a source code using the c, (c-cedilla
character) is runnable in France but not in the U.S.

   Some systems also have problems with parsing numbers using the
`scanf' functions if an other but the `LC_ALL' locale is used.  The
standards say that additional formats but the one known in the `"C"'
locale might be recognized.  But some systems seem to reject numbers in
the `"C"' locale format.  In some situation, it might also be a problem
with the notation itself which makes it impossible to recognize whether
the number is in the `"C"' locale or the local format.  This can happen
if thousands separator characters are used.  Some locales define this
character according to the national conventions to `'.'' which is the
same character used in the `"C"' locale to denote the decimal point.

   So it is sometimes necessary to replace the `LC_ALL' line in the
code above by a sequence of `setlocale' lines

     {
       ...
       setlocale (LC_CTYPE, "");
       setlocale (LC_MESSAGES, "");
       ...
     }

On all POSIX conformant systems the locale categories `LC_CTYPE',
`LC_MESSAGES', `LC_COLLATE', `LC_MONETARY', `LC_NUMERIC', and `LC_TIME'
are available.  On some systems which are only ISO C compliant,
`LC_MESSAGES' is missing, but a substitute for it is defined in GNU
gettext's `<libintl.h>'.

   Note that changing the `LC_CTYPE' also affects the functions
declared in the `<ctype.h>' standard header.  If this is not desirable
in your application (for example in a compiler's parser), you can use a
set of substitute functions which hardwire the C locale, such as found
in the `<c-ctype.h>' and `<c-ctype.c>' files in the gettext source
distribution.

   It is also possible to switch the locale forth and back between the
environment dependent locale and the C locale, but this approach is
normally avoided because a `setlocale' call is expensive, because it is
tedious to determine the places where a locale switch is needed in a
large program's source, and because switching a locale is not
multithread-safe.


File: gettext.info,  Node: Preparing Strings,  Next: Mark Keywords,  Prev: Triggering,  Up: Sources

Preparing Translatable Strings
==============================

Before strings can be marked for translations, they sometimes need to
be adjusted.  Usually preparing a string for translation is done right
before marking it, during the marking phase which is described in the
next sections.  What you have to keep in mind while doing that is the
following.

   * Decent English style.

   * Entire sentences.

   * Split at paragraphs.

   * Use format strings instead of string concatenation.

Let's look at some examples of these guidelines.

   Translatable strings should be in good English style.  If slang
language with abbreviations and shortcuts is used, often translators
will not understand the message and will produce very inappropriate
translations.

     "%s: is parameter\n"

This is nearly untranslatable: Is the displayed item _a_ parameter or
_the_ parameter?

     "No match"

The ambiguity in this message makes it ununderstandable: Is the program
attempting to set something on fire? Does it mean "The given object does
not match the template"? Does it mean "The template does not fit for any
of the objects"?

   In both cases, adding more words to the message will help both the
translator and the English speaking user.

   Translatable strings should be entire sentences.  It is often not
possible to translate single verbs or adjectives in a substitutable way.

     printf ("File %s is %s protected", filename, rw ? "write" : "read");

Most translators will not look at the source and will thus only see the
string `"File %s is %s protected"', which is unintelligible.  Change
this to

     printf (rw ? "File %s is write protected" : "File %s is read protected",
             filename);

This way the translator will not only understand the message, she will
also be able to find the appropriate grammatical construction.  The
French translator for example translates "write protected" like
"protected against writing".

   Entire sentences are also important because in many languages, the
declination of some word in a sentence depends on the gender or the
number (singular/plural) of another part of the sentence.  There are
usually more interdependencies between words than in English.  The
consequence is that asking a translator to translate two half-sentences
and then combining these two half-sentences through dumb string
concatenation will not work, for many languages, even though it would
work for English.  That's why translators need to handle entire
sentences.

   Often sentences don't fit into a single line.  If a sentence is
output using two subsequent `printf' statements, like this

     printf ("Locale charset \"%s\" is different from\n", lcharset);
     printf ("input file charset \"%s\".\n", fcharset);

the translator would have to translate two half sentences, but nothing
in the POT file would tell her that the two half sentences belong
together.  It is necessary to merge the two `printf' statements so that
the translator can handle the entire sentence at once and decide at
which place to insert a line break in the translation (if at all):

     printf ("Locale charset \"%s\" is different from\n\
     input file charset \"%s\".\n", lcharset, fcharset);

   You may now ask: how about two or more adjacent sentences? Like in
this case:

     puts ("Apollo 13 scenario: Stack overflow handling failed.");
     puts ("On the next stack overflow we will crash!!!");

Should these two statements merged into a single one? I would recommend
to merge them if the two sentences are related to each other, because
then it makes it easier for the translator to understand and translate
both.  On the other hand, if one of the two messages is a stereotypic
one, occurring in other places as well, you will do a favour to the
translator by not merging the two.  (Identical messages occurring in
several places are combined by xgettext, so the translator has to
handle them once only.)

   Translatable strings should be limited to one paragraph; don't let a
single message be longer than ten lines.  The reason is that when the
translatable string changes, the translator is faced with the task of
updating the entire translated string.  Maybe only a single word will
have changed in the English string, but the translator doesn't see that
(with the current translation tools), therefore she has to proofread
the entire message.

   Many GNU programs have a `--help' output that extends over several
screen pages.  It is a courtesy towards the translators to split such a
message into several ones of five to ten lines each.  While doing that,
you can also attempt to split the documented options into groups, such
as the input options, the output options, and the informative output
options.  This will help every user to find the option he is looking
for.

   Hardcoded string concatenation is sometimes used to construct English
strings:

     strcpy (s, "Replace ");
     strcat (s, object1);
     strcat (s, " with ");
     strcat (s, object2);
     strcat (s, "?");

In order to present to the translator only entire sentences, and also
because in some languages the translator might want to swap the order
of `object1' and `object2', it is necessary to change this to use a
format string:

     sprintf (s, "Replace %s with %s?", object1, object2);

   A similar case is compile time concatenation of strings.  The ISO C
99 include file `<inttypes.h>' contains a macro `PRId64' that can be
used as a formatting directive for outputting an `int64_t' integer
through `printf'.  It expands to a constant string, usually "d" or "ld"
or "lld" or something like this, depending on the platform.  Assume you
have code like

     printf ("The amount is %0" PRId64 "\n", number);

The `gettext' tools and library have special support for these
`<inttypes.h>' macros.  You can therefore simply write

     printf (gettext ("The amount is %0" PRId64 "\n"), number);

The PO file will contain the string "The amount is %0<PRId64>\n".  The
translators will provide a translation containing "%0<PRId64>" as well,
and at runtime the `gettext' function's result will contain the
appropriate constant string, "d" or "ld" or "lld".

   This works only for the predefined `<inttypes.h>' macros.  If you
have defined your own similar macros, let's say `MYPRId64', that are
not known to `xgettext', the solution for this problem is to change the
code like this:

     char buf1[100];
     sprintf (buf1, "%0" MYPRId64, number);
     printf (gettext ("The amount is %s\n"), buf1);

   This means, you put the platform dependent code in one statement,
and the internationalization code in a different statement.  Note that
a buffer length of 100 is safe, because all available hardware integer
types are limited to 128 bits, and to print a 128 bit integer one needs
at most 54 characters, regardless whether in decimal, octal or
hexadecimal.

   All this applies to other programming languages as well.  For
example, in Java, string contenation is very frequently used, because
it is a compiler built-in operator.  Like in C, in Java, you would
change

     System.out.println("Replace "+object1+" with "+object2+"?");

into a statement involving a format string:

     System.out.println(
         MessageFormat.format("Replace {0} with {1}?",
                              new Object[] { object1, object2 }));


File: gettext.info,  Node: Mark Keywords,  Next: Marking,  Prev: Preparing Strings,  Up: Sources

How Marks Appear in Sources
===========================

All strings requiring translation should be marked in the C sources.
Marking is done in such a way that each translatable string appears to
be the sole argument of some function or preprocessor macro.  There are
only a few such possible functions or macros meant for translation, and
their names are said to be marking keywords.  The marking is attached
to strings themselves, rather than to what we do with them.  This
approach has more uses.  A blatant example is an error message produced
by formatting.  The format string needs translation, as well as some
strings inserted through some `%s' specification in the format, while
the result from `sprintf' may have so many different instances that it
is impractical to list them all in some `error_string_out()' routine,
say.

   This marking operation has two goals.  The first goal of marking is
for triggering the retrieval of the translation, at run time.  The
keyword are possibly resolved into a routine able to dynamically return
the proper translation, as far as possible or wanted, for the argument
string.  Most localizable strings are found in executable positions,
that is, attached to variables or given as parameters to functions.
But this is not universal usage, and some translatable strings appear
in structured initializations.  *Note Special cases::.

   The second goal of the marking operation is to help `xgettext' at
properly extracting all translatable strings when it scans a set of
program sources and produces PO file templates.

   The canonical keyword for marking translatable strings is `gettext',
it gave its name to the whole GNU `gettext' package.  For packages
making only light use of the `gettext' keyword, macro or function, it
is easily used _as is_.  However, for packages using the `gettext'
interface more heavily, it is usually more convenient to give the main
keyword a shorter, less obtrusive name.  Indeed, the keyword might
appear on a lot of strings all over the package, and programmers
usually do not want nor need their program sources to remind them
forcefully, all the time, that they are internationalized.  Further, a
long keyword has the disadvantage of using more horizontal space,
forcing more indentation work on sources for those trying to keep them
within 79 or 80 columns.

   Many packages use `_' (a simple underline) as a keyword, and write
`_("Translatable string")' instead of `gettext ("Translatable
string")'.  Further, the coding rule, from GNU standards, wanting that
there is a space between the keyword and the opening parenthesis is
relaxed, in practice, for this particular usage.  So, the textual
overhead per translatable string is reduced to only three characters:
the underline and the two parentheses.  However, even if GNU `gettext'
uses this convention internally, it does not offer it officially.  The
real, genuine keyword is truly `gettext' indeed.  It is fairly easy for
those wanting to use `_' instead of `gettext' to declare:

     #include <libintl.h>
     #define _(String) gettext (String)

instead of merely using `#include <libintl.h>'.

   Later on, the maintenance is relatively easy.  If, as a programmer,
you add or modify a string, you will have to ask yourself if the new or
altered string requires translation, and include it within `_()' if you
think it should be translated.  `"%s: %d"' is an example of string
_not_ requiring translation!


File: gettext.info,  Node: Marking,  Next: c-format Flag,  Prev: Mark Keywords,  Up: Sources

Marking Translatable Strings
============================

In PO mode, one set of features is meant more for the programmer than
for the translator, and allows him to interactively mark which strings,
in a set of program sources, are translatable, and which are not.  Even
if it is a fairly easy job for a programmer to find and mark such
strings by other means, using any editor of his choice, PO mode makes
this work more comfortable.  Further, this gives translators who feel a
little like programmers, or programmers who feel a little like
translators, a tool letting them work at marking translatable strings
in the program sources, while simultaneously producing a set of
translation in some language, for the package being internationalized.

   The set of program sources, targetted by the PO mode commands
describe here, should have an Emacs tags table constructed for your
project, prior to using these PO file commands.  This is easy to do.
In any shell window, change the directory to the root of your project,
then execute a command resembling:

     etags src/*.[hc] lib/*.[hc]

presuming here you want to process all `.h' and `.c' files from the
`src/' and `lib/' directories.  This command will explore all said
files and create a `TAGS' file in your root directory, somewhat
summarizing the contents using a special file format Emacs can
understand.

   For packages following the GNU coding standards, there is a make
goal `tags' or `TAGS' which constructs the tag files in all directories
and for all files containing source code.

   Once your `TAGS' file is ready, the following commands assist the
programmer at marking translatable strings in his set of sources.  But
these commands are necessarily driven from within a PO file window, and
it is likely that you do not even have such a PO file yet.  This is not
a problem at all, as you may safely open a new, empty PO file, mainly
for using these commands.  This empty PO file will slowly fill in while
you mark strings as translatable in your program sources.

`,'
     Search through program sources for a string which looks like a
     candidate for translation (`po-tags-search').

`M-,'
     Mark the last string found with `_()' (`po-mark-translatable').

`M-.'
     Mark the last string found with a keyword taken from a set of
     possible keywords.  This command with a prefix allows some
     management of these keywords (`po-select-mark-and-mark').


   The `,' (`po-tags-search') command searches for the next occurrence
of a string which looks like a possible candidate for translation, and
displays the program source in another Emacs window, positioned in such
a way that the string is near the top of this other window.  If the
string is too big to fit whole in this window, it is positioned so only
its end is shown.  In any case, the cursor is left in the PO file
window.  If the shown string would be better presented differently in
different native languages, you may mark it using `M-,' or `M-.'.
Otherwise, you might rather ignore it and skip to the next string by
merely repeating the `,' command.

   A string is a good candidate for translation if it contains a
sequence of three or more letters.  A string containing at most two
letters in a row will be considered as a candidate if it has more
letters than non-letters.  The command disregards strings containing no
letters, or isolated letters only.  It also disregards strings within
comments, or strings already marked with some keyword PO mode knows
(see below).

   If you have never told Emacs about some `TAGS' file to use, the
command will request that you specify one from the minibuffer, the
first time you use the command.  You may later change your `TAGS' file
by using the regular Emacs command `M-x visit-tags-table', which will
ask you to name the precise `TAGS' file you want to use.  *Note Tag
Tables: (emacs)Tags.

   Each time you use the `,' command, the search resumes from where it
was left by the previous search, and goes through all program sources,
obeying the `TAGS' file, until all sources have been processed.
However, by giving a prefix argument to the command (`C-u ,'), you may
request that the search be restarted all over again from the first
program source; but in this case, strings that you recently marked as
translatable will be automatically skipped.

   Using this `,' command does not prevent using of other regular Emacs
tags commands.  For example, regular `tags-search' or
`tags-query-replace' commands may be used without disrupting the
independent `,' search sequence.  However, as implemented, the
_initial_ `,' command (or the `,' command is used with a prefix) might
also reinitialize the regular Emacs tags searching to the first tags
file, this reinitialization might be considered spurious.

   The `M-,' (`po-mark-translatable') command will mark the recently
found string with the `_' keyword.  The `M-.'
(`po-select-mark-and-mark') command will request that you type one
keyword from the minibuffer and use that keyword for marking the
string.  Both commands will automatically create a new PO file
untranslated entry for the string being marked, and make it the current
entry (making it easy for you to immediately proceed to its
translation, if you feel like doing it right away).  It is possible
that the modifications made to the program source by `M-,' or `M-.'
render some source line longer than 80 columns, forcing you to break
and re-indent this line differently.  You may use the `O' command from
PO mode, or any other window changing command from Emacs, to break out
into the program source window, and do any needed adjustments.  You
will have to use some regular Emacs command to return the cursor to the
PO file window, if you want command `,' for the next string, say.

   The `M-.' command has a few built-in speedups, so you do not have to
explicitly type all keywords all the time.  The first such speedup is
that you are presented with a _preferred_ keyword, which you may accept
by merely typing `<RET>' at the prompt.  The second speedup is that you
may type any non-ambiguous prefix of the keyword you really mean, and
the command will complete it automatically for you.  This also means
that PO mode has to _know_ all your possible keywords, and that it will
not accept mistyped keywords.

   If you reply `?' to the keyword request, the command gives a list of
all known keywords, from which you may choose.  When the command is
prefixed by an argument (`C-u M-.'), it inhibits updating any program
source or PO file buffer, and does some simple keyword management
instead.  In this case, the command asks for a keyword, written in
full, which becomes a new allowed keyword for later `M-.' commands.
Moreover, this new keyword automatically becomes the _preferred_
keyword for later commands.  By typing an already known keyword in
response to `C-u M-.', one merely changes the _preferred_ keyword and
does nothing more.

   All keywords known for `M-.' are recognized by the `,' command when
scanning for strings, and strings already marked by any of those known
keywords are automatically skipped.  If many PO files are opened
simultaneously, each one has its own independent set of known keywords.
There is no provision in PO mode, currently, for deleting a known
keyword, you have to quit the file (maybe using `q') and reopen it
afresh.  When a PO file is newly brought up in an Emacs window, only
`gettext' and `_' are known as keywords, and `gettext' is preferred for
the `M-.' command.  In fact, this is not useful to prefer `_', as this
one is already built in the `M-,' command.


File: gettext.info,  Node: c-format Flag,  Next: Special cases,  Prev: Marking,  Up: Sources

Special Comments preceding Keywords
===================================

In C programs strings are often used within calls of functions from the
`printf' family.  The special thing about these format strings is that
they can contain format specifiers introduced with `%'.  Assume we have
the code

     printf (gettext ("String `%s' has %d characters\n"), s, strlen (s));

A possible German translation for the above string might be:

     "%d Zeichen lang ist die Zeichenkette `%s'"

   A C programmer, even if he cannot speak German, will recognize that
there is something wrong here.  The order of the two format specifiers
is changed but of course the arguments in the `printf' don't have.
This will most probably lead to problems because now the length of the
string is regarded as the address.

   To prevent errors at runtime caused by translations the `msgfmt'
tool can check statically whether the arguments in the original and the
translation string match in type and number.  If this is not the case
and the `-c' option has been passed to `msgfmt', `msgfmt' will give an
error and refuse to produce a MO file.  Thus consequent use of `msgfmt
-c' will catch the error, so that it cannot cause cause problems at
runtime.

If the word order in the above German translation would be correct one
would have to write

     "%2$d Zeichen lang ist die Zeichenkette `%1$s'"

The routines in `msgfmt' know about this special notation.

   Because not all strings in a program must be format strings it is not
useful for `msgfmt' to test all the strings in the `.po' file.  This
might cause problems because the string might contain what looks like a
format specifier, but the string is not used in `printf'.

   Therefore the `xgettext' adds a special tag to those messages it
thinks might be a format string.  There is no absolute rule for this,
only a heuristic.  In the `.po' file the entry is marked using the
`c-format' flag in the `#,' comment line (*note PO Files::).

   The careful reader now might say that this again can cause problems.
The heuristic might guess it wrong.  This is true and therefore
`xgettext' knows about a special kind of comment which lets the
programmer take over the decision.  If in the same line as or the
immediately preceding line to the `gettext' keyword the `xgettext'
program finds a comment containing the words `xgettext:c-format', it
will mark the string in any case with the `c-format' flag.  This kind
of comment should be used when `xgettext' does not recognize the string
as a format string but it really is one and it should be tested.
Please note that when the comment is in the same line as the `gettext'
keyword, it must be before the string to be translated.

   This situation happens quite often.  The `printf' function is often
called with strings which do not contain a format specifier.  Of course
one would normally use `fputs' but it does happen.  In this case
`xgettext' does not recognize this as a format string but what happens
if the translation introduces a valid format specifier?  The `printf'
function will try to access one of the parameters but none exists
because the original code does not pass any parameters.

   `xgettext' of course could make a wrong decision the other way
round, i.e. a string marked as a format string actually is not a format
string.  In this case the `msgfmt' might give too many warnings and
would prevent translating the `.po' file.  The method to prevent this
wrong decision is similar to the one used above, only the comment to
use must contain the string `xgettext:no-c-format'.

   If a string is marked with `c-format' and this is not correct the
user can find out who is responsible for the decision.  See *Note
xgettext Invocation:: to see how the `--debug' option can be used for
solving this problem.


File: gettext.info,  Node: Special cases,  Next: Names,  Prev: c-format Flag,  Up: Sources

Special Cases of Translatable Strings
=====================================

The attentive reader might now point out that it is not always possible
to mark translatable string with `gettext' or something like this.
Consider the following case:

     {
       static const char *messages[] = {
         "some very meaningful message",
         "and another one"
       };
       const char *string;
       ...
       string
         = index > 1 ? "a default message" : messages[index];
     
       fputs (string);
       ...
     }

   While it is no problem to mark the string `"a default message"' it
is not possible to mark the string initializers for `messages'.  What
is to be done?  We have to fulfill two tasks.  First we have to mark the
strings so that the `xgettext' program (*note xgettext Invocation::)
can find them, and second we have to translate the string at runtime
before printing them.

   The first task can be fulfilled by creating a new keyword, which
names a no-op.  For the second we have to mark all access points to a
string from the array.  So one solution can look like this:

     #define gettext_noop(String) String
     
     {
       static const char *messages[] = {
         gettext_noop ("some very meaningful message"),
         gettext_noop ("and another one")
       };
       const char *string;
       ...
       string
         = index > 1 ? gettext ("a default message") : gettext (messages[index]);
     
       fputs (string);
       ...
     }

   Please convince yourself that the string which is written by `fputs'
is translated in any case.  How to get `xgettext' know the additional
keyword `gettext_noop' is explained in *Note xgettext Invocation::.

   The above is of course not the only solution.  You could also come
along with the following one:

     #define gettext_noop(String) String
     
     {
       static const char *messages[] = {
         gettext_noop ("some very meaningful message",
         gettext_noop ("and another one")
       };
       const char *string;
       ...
       string
         = index > 1 ? gettext_noop ("a default message") : messages[index];
     
       fputs (gettext (string));
       ...
     }

   But this has a drawback.  The programmer has to take care that he
uses `gettext_noop' for the string `"a default message"'.  A use of
`gettext' could have in rare cases unpredictable results.

   One advantage is that you need not make control flow analysis to make
sure the output is really translated in any case.  But this analysis is
generally not very difficult.  If it should be in any situation you can
use this second method in this situation.


File: gettext.info,  Node: Names,  Prev: Special cases,  Up: Sources

Marking Proper Names for Translation
====================================

Should names of persons, cities, locations etc. be marked for
translation or not?  People who only know languages that can be written
with Latin letters (English, Spanish, French, German, etc.) are tempted
to say "no", because names usually do not change when transported
between these languages.  However, in general when translating from one
script to another, names are translated too, usually phonetically or by
transliteration.  For example, Russian or Greek names are converted to
the Latin alphabet when being translated to English, and English or
French names are converted to the Katakana script when being translated
to Japanese.  This is necessary because the speakers of the target
language in general cannot read the script the name is originally
written in.

   As a programmer, you should therefore make sure that names are marked
for translation, with a special comment telling the translators that it
is a proper name and how to pronounce it.  Like this:

     printf (_("Written by %s.\n"),
             /* TRANSLATORS: This is a proper name.  See the gettext
                manual, section Names.  Note this is actually a non-ASCII
                name: The first name is (with Unicode escapes)
                "Fran\u00e7ois" or (with HTML entities) "Fran&ccedil;ois".
                Pronounciation is like "fraa-swa pee-nar".  */
             _("Francois Pinard"));

   As a translator, you should use some care when translating names,
because it is frustrating if people see their names mutilated or
distorted.  If your language uses the Latin script, all you need to do
is to reproduce the name as perfectly as you can within the usual
character set of your language.  In this particular case, this means to
provide a translation containing the c-cedilla character.  If your
language uses a different script and the people speaking it don't
usually read Latin words, it means transliteration; but you should
still give, in parentheses, the original writing of the name - for the
sake of the people that do read the Latin script.  Here is an example,
using Greek as the target script:

     #. This is a proper name.  See the gettext
     #. manual, section Names.  Note this is actually a non-ASCII
     #. name: The first name is (with Unicode escapes)
     #. "Fran\u00e7ois" or (with HTML entities) "Fran&ccedil;ois".
     #. Pronounciation is like "fraa-swa pee-nar".
     msgid "Francois Pinard"
     msgstr "\phi\rho\alpha\sigma\omicron\alpha \pi\iota\nu\alpha\rho"
            " (Francois Pinard)"

   Because translation of names is such a sensitive domain, it is a good
idea to test your translation before submitting it.

   The translation project <http://sourceforge.net/projects/translation>
has set up a POT file and translation domain consisting of program
author names, with better facilities for the translator than those
presented here.  Namely, there the original name is written directly in
Unicode (rather than with Unicode escapes or HTML entities), and the
pronounciation is denoted using the International Phonetic Alphabet (see
<http://www.wikipedia.org/wiki/International_Phonetic_Alphabet>).

   However, we don't recommend this approach for all POT files in all
packages, because this would force translators to use PO files in UTF-8
encoding, which is - in the current state of software (as of 2003) - a
major hassle for translators using GNU Emacs or XEmacs with po-mode.


File: gettext.info,  Node: Template,  Next: Creating,  Prev: Sources,  Up: Top

Making the PO Template File
***************************

After preparing the sources, the programmer creates a PO template file.
This section explains how to use `xgettext' for this purpose.

   `xgettext' creates a file named `DOMAINNAME.po'.  You should then
rename it to `DOMAINNAME.pot'.  (Why doesn't `xgettext' create it under
the name `DOMAINNAME.pot' right away?  The answer is: for historical
reasons.  When `xgettext' was specified, the distinction between a PO
file and PO file template was fuzzy, and the suffix `.pot' wasn't in
use at that time.)

* Menu:

* xgettext Invocation::         Invoking the `xgettext' Program


File: gettext.info,  Node: xgettext Invocation,  Prev: Template,  Up: Template

Invoking the `xgettext' Program
===============================

     xgettext [OPTION] [INPUTFILE] ...

   The `xgettext' program extracts translatable strings from given
input files.

Input file location
-------------------

`INPUTFILE ...'
     Input files.

`-f FILE'
`--files-from=FILE'
     Read the names of the input files from FILE instead of getting
     them from the command line.

`-D DIRECTORY'
`--directory=DIRECTORY'
     Add DIRECTORY to the list of directories.  Source files are
     searched relative to this list of directories.  The resulting `.po'
     file will be written relative to the current directory, though.


   If INPUTFILE is `-', standard input is read.

Output file location
--------------------

`-d NAME'
`--default-domain=NAME'
     Use `NAME.po' for output (instead of `messages.po').

`-o FILE'
`--output=FILE'
     Write output to specified file (instead of `NAME.po' or
     `messages.po').

`-p DIR'
`--output-dir=DIR'
     Output files will be placed in directory DIR.


   If the output FILE is `-' or `/dev/stdout', the output is written to
standard output.

Choice of input file language
-----------------------------

`-L NAME'
`--language=NAME'
     Specifies the language of the input files.  The supported languages
     are `C', `C++', `ObjectiveC', `PO', `Python', `Lisp', `EmacsLisp',
     `librep', `Smalltalk', `Java', `JavaProperties', `awk', `YCP',
     `Tcl', `Perl', `PHP', `GCC-source', `NXStringTable', `RST',
     `Glade'.

`-C'
`--c++'
     This is a shorthand for `--language=C++'.


   By default the language is guessed depending on the input file name
extension.

Input file interpretation
-------------------------

`--from-code=NAME'
     Specifies the encoding of the input files.  This option is needed
     only if some untranslated message strings or their corresponding
     comments contain non-ASCII characters.  Note that Python, Tcl, and
     Glade input files are always assumed to be in UTF-8, regardless of
     this option.


   By default the input files are assumed to be in ASCII.

Operation mode
--------------

`-j'
`--join-existing'
     Join messages with existing file.

`-x FILE'
`--exclude-file=FILE'
     Entries from FILE are not extracted.  FILE should be a PO or POT
     file.

`-c [TAG]'
`--add-comments[=TAG]'
     Place comment block with TAG (or those preceding keyword lines) in
     output file.


Language specific options
-------------------------

`-a'
`--extract-all'
     Extract all strings.

     This option has an effect with most languages, namely C, C++,
     ObjectiveC, Shell, Python, Lisp, EmacsLisp, librep, Java, awk,
     Tcl, Perl, PHP, GCC-source, Glade.

`-k KEYWORDSPEC'
`--keyword[=KEYWORDSPEC]'
     Additional keyword to be looked for (without KEYWORDSPEC means not
     to use default keywords).

     If KEYWORDSPEC is a C identifer ID, `xgettext' looks for strings
     in the first argument of each call to the function or macro ID.
     If KEYWORDSPEC is of the form `ID:ARGNUM', `xgettext' looks for
     strings in the ARGNUMth argument of the call.  If KEYWORDSPEC is
     of the form `ID:ARGNUM1,ARGNUM2', `xgettext' looks for strings in
     the ARGNUM1st argument and in the ARGNUM2nd argument of the call,
     and treats them as singular/plural variants for a message with
     plural handling.
     The default keyword specifications, which are always looked for if
     not explicitly disabled, are `gettext', `dgettext:2',
     `dcgettext:2', `ngettext:1,2', `dngettext:2,3', `dcngettext:2,3',
     and `gettext_noop'.
     This option has an effect with most languages, namely C, C++,
     ObjectiveC, Shell, Python, Lisp, EmacsLisp, librep, Java, awk,
     Tcl, Perl, PHP, GCC-source, Glade.

`--flag=WORD:ARG:FLAG'
     Specifies additional flags for strings occurring as part of the
     ARGth argument of the function WORD.  The possible flags are the
     possible format string indicators, such as `c-format', and their
     negations, such as `no-c-format', possibly prefixed with `pass-'.
     The meaning of `--flag=FUNCTION:ARG:LANG-format' is that in
     language LANG, the specified FUNCTION expects as ARGth argument a
     format string.  (For those of you familiar with GCC function
     attributes, `--flag=FUNCTION:ARG:c-format' is roughly equivalent
     to the declaration `__attribute__ ((__format__ (__printf__, ARG,
     ...)))' attached to FUNCTION in a C source file.)  For example, if
     you use the `error' function from GNU libc, you can specify its
     behaviour through `--flag=error:3:c-format'.  The effect of this
     specification is that `xgettext' will mark as format strings all
     `gettext' invocations that occur as ARGth argument of FUNCTION.
     This is useful when such strings contain no format string
     directives: together with the checks done by `msgfmt -c' it will
     ensure that translators cannot accidentally use format string
     directives that would lead to a crash at runtime.
     The meaning of `--flag=FUNCTION:ARG:pass-LANG-format' is that in
     language LANG, if the FUNCTION call occurs in a position that must
     yield a format string, then its ARGth argument must yield a format
     string of the same type as well.  (If you know GCC function
     attributes, the `--flag=FUNCTION:ARG:pass-c-format' option is
     roughly equivalent to the declaration `__attribute__
     ((__format_arg__ (ARG)))' attached to FUNCTION in a C source file.)
     For example, if you use the `_' shortcut for the `gettext'
     function, you should use `--flag=_:1:pass-c-format'.  The effect
     of this specification is that `xgettext' will propagate a format
     string requirement for a `_("string")' call to its first argument,
     the literal `"string"', and thus mark it as a format string.  This
     is useful when such strings contain no format string directives:
     together with the checks done by `msgfmt -c' it will ensure that
     translators cannot accidentally use format string directives that
     would lead to a crash at runtime.

`-T'
`--trigraphs'
     Understand ANSI C trigraphs for input.
     This option has an effect only with the languages C, C++,
     ObjectiveC.

`--qt'
     Recognize Qt format strings.
     This option has an effect only with the language C++.

`--debug'
     Use the flags `c-format' and `possible-c-format' to show who was
     responsible for marking a message as a format string.  The latter
     form is used if the `xgettext' program decided, the format form is
     used if the programmer prescribed it.

     By default only the `c-format' form is used.  The translator should
     not have to care about these details.


   This implementation of `xgettext' is able to process a few awkward
cases, like strings in preprocessor macros, ANSI concatenation of
adjacent strings, and escaped end of lines for continued strings.

Output details
--------------

`--force-po'
     Always write an output file even if no message is defined.

`-i'
`--indent'
     Write the .po file using indented style.

`--no-location'
     Do not write `#: FILENAME:LINE' lines.

`-n'
`--add-location'
     Generate `#: FILENAME:LINE' lines (default).

`--strict'
     Write out a strict Uniforum conforming PO file.  Note that this
     Uniforum format should be avoided because it doesn't support the
     GNU extensions.

`--properties-output'
     Write out a Java ResourceBundle in Java `.properties' syntax.  Note
     that this file format doesn't support plural forms and silently
     drops obsolete messages.

`--stringtable-output'
     Write out a NeXTstep/GNUstep localized resource file in `.strings'
     syntax.  Note that this file format doesn't support plural forms.

`-w NUMBER'
`--width=NUMBER'
     Set the output page width.  Long strings in the output files will
     be split across multiple lines in order to ensure that each line's
     width (= number of screen columns) is less or equal to the given
     NUMBER.

`--no-wrap'
     Do not break long message lines.  Message lines whose width
     exceeds the output page width will not be split into several
     lines.  Only file reference lines which are wider than the output
     page width will be split.

`-s'
`--sort-output'
     Generate sorted output.  Note that using this option makes it much
     harder for the translator to understand each message's context.

`-F'
`--sort-by-file'
     Sort output by file location.

`--omit-header'
     Don't write header with `msgid ""' entry.

     This is useful for testing purposes because it eliminates a source
     of variance for generated `.gmo' files.  With `--omit-header', two
     invocations of `xgettext' on the same files with the same options
     at different times are guaranteed to produce the same results.

`--copyright-holder=STRING'
     Set the copyright holder in the output.  STRING should be the
     copyright holder of the surrounding package.  (Note that the msgstr
     strings, extracted from the package's sources, belong to the
     copyright holder of the package.)  Translators are expected to
     transfer or disclaim the copyright for their translations, so that
     package maintainers can distribute them without legal risk.  If
     STRING is empty, the output files are marked as being in the
     public domain; in this case, the translators are expected to
     disclaim their copyright, again so that package maintainers can
     distribute them without legal risk.

     The default value for STRING is the Free Software Foundation, Inc.,
     simply because `xgettext' was first used in the GNU project.

`--foreign-user'
     Omit FSF copyright in output.  This option is equivalent to
     `--copyright-holder='''.  It can be useful for packages outside
     the GNU project that want their translations to be in the public
     domain.

`--msgid-bugs-address=EMAIL@ADDRESS'
     Set the reporting address for msgid bugs.  This is the email
     address or URL to which the translators shall report bugs in the
     untranslated strings:

        - Strings which are not entire sentences, see the maintainer
          guidelines in *Note Preparing Strings::.

        - Strings which use unclear terms or require additional context
          to be understood.

        - Strings which make invalid assumptions about notation of
          date, time or money.

        - Pluralisation problems.

        - Incorrect English spelling.

        - Incorrect formatting.

     It can be your email address, or a mailing list address where
     translators can write to without being subscribed, or the URL of a
     web page through which the translators can contact you.

     The default value is empty, which means that translators will be
     clueless!  Don't forget to specify this option.

`-m [STRING]'
`--msgstr-prefix[=STRING]'
     Use STRING (or "" if not specified) as prefix for msgstr entries.

`-M [STRING]'
`--msgstr-suffix[=STRING]'
     Use STRING (or "" if not specified) as suffix for msgstr entries.


Informative output
------------------

`-h'
`--help'
     Display this help and exit.

`-V'
`--version'
     Output version information and exit.



File: gettext.info,  Node: Creating,  Next: Updating,  Prev: Template,  Up: Top

Creating a New PO File
**********************

When starting a new translation, the translator creates a file called
`LANG.po', as a copy of the `PACKAGE.pot' template file with
modifications in the initial comments (at the beginning of the file)
and in the header entry (the first entry, near the beginning of the
file).

   The easiest way to do so is by use of the `msginit' program.  For
example:

     $ cd PACKAGE-VERSION
     $ cd po
     $ msginit

   The alternative way is to do the copy and modifications by hand.  To
do so, the translator copies `PACKAGE.pot' to `LANG.po'.  Then she
modifies the initial comments and the header entry of this file.

* Menu:

* msginit Invocation::          Invoking the `msginit' Program
* Header Entry::                Filling in the Header Entry


File: gettext.info,  Node: msginit Invocation,  Next: Header Entry,  Prev: Creating,  Up: Creating

Invoking the `msginit' Program
==============================

     msginit [OPTION]

   The `msginit' program creates a new PO file, initializing the meta
information with values from the user's environment.

Input file location
-------------------

`-i INPUTFILE'
`--input=INPUTFILE'
     Input POT file.


   If no INPUTFILE is given, the current directory is searched for the
POT file.  If it is `-', standard input is read.

Output file location
--------------------

`-o FILE'
`--output-file=FILE'
     Write output to specified PO file.


   If no output file is given, it depends on the `--locale' option or
the user's locale setting.  If it is `-', the results are written to
standard output.

Input file syntax
-----------------

`-P'
`--properties-input'
     Assume the input file is a Java ResourceBundle in Java
     `.properties' syntax, not in PO file syntax.

`--stringtable-input'
     Assume the input file is a NeXTstep/GNUstep localized resource
     file in `.strings' syntax, not in PO file syntax.


Output details
--------------

`-l LL_CC'
`--locale=LL_CC'
     Set target locale.  LL should be a language code, and CC should be
     a country code.  The command `locale -a' can be used to output a
     list of all installed locales.  The default is the user's locale
     setting.

`--no-translator'
     Declares that the PO file will not have a human translator and is
     instead automatically generated.

`-p'
`--properties-output'
     Write out a Java ResourceBundle in Java `.properties' syntax.  Note
     that this file format doesn't support plural forms and silently
     drops obsolete messages.

`--stringtable-output'
     Write out a NeXTstep/GNUstep localized resource file in `.strings'
     syntax.  Note that this file format doesn't support plural forms.

`-w NUMBER'
`--width=NUMBER'
     Set the output page width.  Long strings in the output files will
     be split across multiple lines in order to ensure that each line's
     width (= number of screen columns) is less or equal to the given
     NUMBER.

`--no-wrap'
     Do not break long message lines.  Message lines whose width
     exceeds the output page width will not be split into several
     lines.  Only file reference lines which are wider than the output
     page width will be split.


Informative output
------------------

`-h'
`--help'
     Display this help and exit.

`-V'
`--version'
     Output version information and exit.



File: gettext.info,  Node: Header Entry,  Prev: msginit Invocation,  Up: Creating

Filling in the Header Entry
===========================

The initial comments "SOME DESCRIPTIVE TITLE", "YEAR" and "FIRST AUTHOR
<EMAIL@ADDRESS>, YEAR" ought to be replaced by sensible information.
This can be done in any text editor; if Emacs is used and it switched
to PO mode automatically (because it has recognized the file's suffix),
you can disable it by typing `M-x fundamental-mode'.

   Modifying the header entry can already be done using PO mode: in
Emacs, type `M-x po-mode RET' and then `RET' again to start editing the
entry.  You should fill in the following fields.

Project-Id-Version
     This is the name and version of the package.

Report-Msgid-Bugs-To
     This has already been filled in by `xgettext'.  It contains an
     email address or URL where you can report bugs in the untranslated
     strings:

        - Strings which are not entire sentences, see the maintainer
          guidelines in *Note Preparing Strings::.

        - Strings which use unclear terms or require additional context
          to be understood.

        - Strings which make invalid assumptions about notation of
          date, time or money.

        - Pluralisation problems.

        - Incorrect English spelling.

        - Incorrect formatting.

POT-Creation-Date
     This has already been filled in by `xgettext'.

PO-Revision-Date
     You don't need to fill this in.  It will be filled by the Emacs PO
     mode when you save the file.

Last-Translator
     Fill in your name and email address (without double quotes).

Language-Team
     Fill in the English name of the language, and the email address or
     homepage URL of the language team you are part of.

     Before starting a translation, it is a good idea to get in touch
     with your translation team, not only to make sure you don't do
     duplicated work, but also to coordinate difficult linguistic
     issues.

     In the Free Translation Project, each translation team has its own
     mailing list.  The up-to-date list of teams can be found at the
     Free Translation Project's homepage,
     `http://www.iro.umontreal.ca/contrib/po/HTML/', in the "National
     teams" area.

Content-Type
     Replace `CHARSET' with the character encoding used for your
     language, in your locale, or UTF-8.  This field is needed for
     correct operation of the `msgmerge' and `msgfmt' programs, as well
     as for users whose locale's character encoding differs from yours
     (see *Note Charset conversion::).

     You get the character encoding of your locale by running the shell
     command `locale charmap'.  If the result is `C' or
     `ANSI_X3.4-1968', which is equivalent to `ASCII' (= `US-ASCII'),
     it means that your locale is not correctly configured.  In this
     case, ask your translation team which charset to use.  `ASCII' is
     not usable for any language except Latin.

     Because the PO files must be portable to operating systems with
     less advanced internationalization facilities, the character
     encodings that can be used are limited to those supported by both
     GNU `libc' and GNU `libiconv'.  These are: `ASCII', `ISO-8859-1',
     `ISO-8859-2', `ISO-8859-3', `ISO-8859-4', `ISO-8859-5',
     `ISO-8859-6', `ISO-8859-7', `ISO-8859-8', `ISO-8859-9',
     `ISO-8859-13', `ISO-8859-14', `ISO-8859-15', `KOI8-R', `KOI8-U',
     `KOI8-T', `CP850', `CP866', `CP874', `CP932', `CP949', `CP950',
     `CP1250', `CP1251', `CP1252', `CP1253', `CP1254', `CP1255',
     `CP1256', `CP1257', `GB2312', `EUC-JP', `EUC-KR', `EUC-TW',
     `BIG5', `BIG5-HKSCS', `GBK', `GB18030', `SHIFT_JIS', `JOHAB',
     `TIS-620', `VISCII', `GEORGIAN-PS', `UTF-8'.

     In the GNU system, the following encodings are frequently used for
     the corresponding languages.

        * `ISO-8859-1' for Afrikaans, Albanian, Basque, Breton,
          Catalan, Cornish, Danish, Dutch, English, Estonian, Faroese,
          Finnish, French, Galician, German, Greenlandic, Icelandic,
          Indonesian, Irish, Italian, Malay, Manx, Norwegian, Occitan,
          Portuguese, Spanish, Swedish, Tagalog, Uzbek, Walloon,

        * `ISO-8859-2' for Bosnian, Croatian, Czech, Hungarian, Polish,
          Romanian, Serbian, Slovak, Slovenian,

        * `ISO-8859-3' for Maltese,

        * `ISO-8859-5' for Macedonian, Serbian,

        * `ISO-8859-6' for Arabic,

        * `ISO-8859-7' for Greek,

        * `ISO-8859-8' for Hebrew,

        * `ISO-8859-9' for Turkish,

        * `ISO-8859-13' for Latvian, Lithuanian, Maori,

        * `ISO-8859-14' for Welsh,

        * `ISO-8859-15' for Basque, Catalan, Dutch, English, Finnish,
          French, Galician, German, Irish, Italian, Portuguese,
          Spanish, Swedish, Walloon,

        * `KOI8-R' for Russian,

        * `KOI8-U' for Ukrainian,

        * `KOI8-T' for Tajik,

        * `CP1251' for Bulgarian, Byelorussian,

        * `GB2312', `GBK', `GB18030' for simplified writing of Chinese,

        * `BIG5', `BIG5-HKSCS' for traditional writing of Chinese,

        * `EUC-JP' for Japanese,

        * `EUC-KR' for Korean,

        * `TIS-620' for Thai,

        * `GEORGIAN-PS' for Georgian,

        * `UTF-8' for any language, including those listed above.

     When single quote characters or double quote characters are used in
     translations for your language, and your locale's encoding is one
     of the ISO-8859-* charsets, it is best if you create your PO files
     in UTF-8 encoding, instead of your locale's encoding.  This is
     because in UTF-8 the real quote characters can be represented
     (single quote characters: U+2018, U+2019, double quote characters:
     U+201C, U+201D), whereas none of ISO-8859-* charsets has them all.
     Users in UTF-8 locales will see the real quote characters,
     whereas users in ISO-8859-* locales will see the vertical
     apostrophe and the vertical double quote instead (because that's
     what the character set conversion will transliterate them to).

     To enter such quote characters under X11, you can change your
     keyboard mapping using the `xmodmap' program.  The X11 names of
     the quote characters are "leftsinglequotemark",
     "rightsinglequotemark", "leftdoublequotemark",
     "rightdoublequotemark", "singlelowquotemark", "doublelowquotemark".

     Note that only recent versions of GNU Emacs support the UTF-8
     encoding: Emacs 20 with Mule-UCS, and Emacs 21.  As of January
     2001, XEmacs doesn't support the UTF-8 encoding.

     The character encoding name can be written in either upper or
     lower case.  Usually upper case is preferred.

Content-Transfer-Encoding
     Set this to `8bit'.

Plural-Forms
     This field is optional.  It is only needed if the PO file has
     plural forms.  You can find them by searching for the
     `msgid_plural' keyword.  The format of the plural forms field is
     described in *Note Plural forms::.


File: gettext.info,  Node: Updating,  Next: Manipulating,  Prev: Creating,  Up: Top

Updating Existing PO Files
**************************

* Menu:

* msgmerge Invocation::         Invoking the `msgmerge' Program
* Translated Entries::          Translated Entries
* Fuzzy Entries::               Fuzzy Entries
* Untranslated Entries::        Untranslated Entries
* Obsolete Entries::            Obsolete Entries
* Modifying Translations::      Modifying Translations
* Modifying Comments::          Modifying Comments
* Subedit::                     Mode for Editing Translations
* C Sources Context::           C Sources Context
* Auxiliary::                   Consulting Auxiliary PO Files
* Compendium::                  Using Translation Compendia


File: gettext.info,  Node: msgmerge Invocation,  Next: Translated Entries,  Prev: Updating,  Up: Updating

Invoking the `msgmerge' Program
===============================

     msgmerge [OPTION] DEF.po REF.pot

   The `msgmerge' program merges two Uniforum style .po files together.
The DEF.po file is an existing PO file with translations which will be
taken over to the newly created file as long as they still match;
comments will be preserved, but extracted comments and file positions
will be discarded.  The REF.pot file is the last created PO file with
up-to-date source references but old translations, or a PO Template file
(generally created by `xgettext'); any translations or comments in the
file will be discarded, however dot comments and file positions will be
preserved.  Where an exact match cannot be found, fuzzy matching is
used to produce better results.

Input file location
-------------------

`DEF.po'
     Translations referring to old sources.

`REF.pot'
     References to the new sources.

`-D DIRECTORY'
`--directory=DIRECTORY'
     Add DIRECTORY to the list of directories.  Source files are
     searched relative to this list of directories.  The resulting `.po'
     file will be written relative to the current directory, though.

`-C FILE'
`--compendium=FILE'
     Specify an additional library of message translations.  *Note
     Compendium::.  This option may be specified more than once.


Operation mode
--------------

`-U'
`--update'
     Update DEF.po.  Do nothing if DEF.po is already up to date.


Output file location
--------------------

`-o FILE'
`--output-file=FILE'
     Write output to specified file.


   The results are written to standard output if no output file is
specified or if it is `-'.

Output file location in update mode
-----------------------------------

The result is written back to DEF.po.

`--backup=CONTROL'
     Make a backup of DEF.po

`--suffix=SUFFIX'
     Override the usual backup suffix.


   The version control method may be selected via the `--backup' option
or through the `VERSION_CONTROL' environment variable.  Here are the
values:

`none'
`off'
     Never make backups (even if `--backup' is given).

`numbered'
`t'
     Make numbered backups.

`existing'
`nil'
     Make numbered backups if numbered backups for this file already
     exist, otherwise make simple backups.

`simple'
`never'
     Always make simple backups.


   The backup suffix is `~', unless set with `--suffix' or the
`SIMPLE_BACKUP_SUFFIX' environment variable.

Operation modifiers
-------------------

`-m'
`--multi-domain'
     Apply REF.pot to each of the domains in DEF.po.

`-N'
`--no-fuzzy-matching'
     Do not use fuzzy matching when an exact match is not found.  This
     may speed up the operation considerably.

Input file syntax
-----------------

`-P'
`--properties-input'
     Assume the input files are Java ResourceBundles in Java
     `.properties' syntax, not in PO file syntax.

`--stringtable-input'
     Assume the input files are NeXTstep/GNUstep localized resource
     files in `.strings' syntax, not in PO file syntax.


Output details
--------------

`--force-po'
     Always write an output file even if it contains no message.

`-i'
`--indent'
     Write the .po file using indented style.

`--no-location'
     Do not write `#: FILENAME:LINE' lines.

`--add-location'
     Generate `#: FILENAME:LINE' lines (default).

`--strict'
     Write out a strict Uniforum conforming PO file.  Note that this
     Uniforum format should be avoided because it doesn't support the
     GNU extensions.

`-p'
`--properties-output'
     Write out a Java ResourceBundle in Java `.properties' syntax.  Note
     that this file format doesn't support plural forms and silently
     drops obsolete messages.

`--stringtable-output'
     Write out a NeXTstep/GNUstep localized resource file in `.strings'
     syntax.  Note that this file format doesn't support plural forms.

`-w NUMBER'
`--width=NUMBER'
     Set the output page width.  Long strings in the output files will
     be split across multiple lines in order to ensure that each line's
     width (= number of screen columns) is less or equal to the given
     NUMBER.

`--no-wrap'
     Do not break long message lines.  Message lines whose width
     exceeds the output page width will not be split into several
     lines.  Only file reference lines which are wider than the output
     page width will be split.

`-s'
`--sort-output'
     Generate sorted output.  Note that using this option makes it much
     harder for the translator to understand each message's context.

`-F'
`--sort-by-file'
     Sort output by file location.


Informative output
------------------

`-h'
`--help'
     Display this help and exit.

`-V'
`--version'
     Output version information and exit.

`-v'
`--verbose'
     Increase verbosity level.

`-q'
`--quiet'
`--silent'
     Suppress progress indicators.



File: gettext.info,  Node: Translated Entries,  Next: Fuzzy Entries,  Prev: msgmerge Invocation,  Up: Updating

Translated Entries
==================

Each PO file entry for which the `msgstr' field has been filled with a
translation, and which is not marked as fuzzy (*note Fuzzy Entries::),
is said to be a "translated" entry.  Only translated entries will later
be compiled by GNU `msgfmt' and become usable in programs.  Other entry
types will be excluded; translation will not occur for them.

   Some commands are more specifically related to translated entry
processing.

`t'
     Find the next translated entry (`po-next-translated-entry').

`T'
     Find the previous translated entry
     (`po-previous-translated-entry').


   The commands `t' (`po-next-translated-entry') and `T'
(`po-previous-translated-entry') move forwards or backwards, chasing
for an translated entry.  If none is found, the search is extended and
wraps around in the PO file buffer.

   Translated entries usually result from the translator having edited
in a translation for them, *Note Modifying Translations::.  However, if
the variable `po-auto-fuzzy-on-edit' is not `nil', the entry having
received a new translation first becomes a fuzzy entry, which ought to
be later unfuzzied before becoming an official, genuine translated
entry.  *Note Fuzzy Entries::.


File: gettext.info,  Node: Fuzzy Entries,  Next: Untranslated Entries,  Prev: Translated Entries,  Up: Updating

Fuzzy Entries
=============

Each PO file entry may have a set of "attributes", which are qualities
given a name and explicitly associated with the translation, using a
special system comment.  One of these attributes has the name `fuzzy',
and entries having this attribute are said to have a fuzzy translation.
They are called fuzzy entries, for short.

   Fuzzy entries, even if they account for translated entries for most
other purposes, usually call for revision by the translator.  Those may
be produced by applying the program `msgmerge' to update an older
translated PO files according to a new PO template file, when this tool
hypothesises that some new `msgid' has been modified only slightly out
of an older one, and chooses to pair what it thinks to be the old
translation for the new modified entry.  The slight alteration in the
original string (the `msgid' string) should often be reflected in the
translated string, and this requires the intervention of the
translator.  For this reason, `msgmerge' might mark some entries as
being fuzzy.

   Also, the translator may decide herself to mark an entry as fuzzy
for her own convenience, when she wants to remember that the entry has
to be later revisited.  So, some commands are more specifically related
to fuzzy entry processing.

`z'
     Find the next fuzzy entry (`po-next-fuzzy-entry').

`Z'
     Find the previous fuzzy entry (`po-previous-fuzzy-entry').

`<TAB>'
     Remove the fuzzy attribute of the current entry (`po-unfuzzy').


   The commands `z' (`po-next-fuzzy-entry') and `Z'
(`po-previous-fuzzy-entry') move forwards or backwards, chasing for a
fuzzy entry.  If none is found, the search is extended and wraps around
in the PO file buffer.

   The command `<TAB>' (`po-unfuzzy') removes the fuzzy attribute
associated with an entry, usually leaving it translated.  Further, if
the variable `po-auto-select-on-unfuzzy' has not the `nil' value, the
`<TAB>' command will automatically chase for another interesting entry
to work on.  The initial value of `po-auto-select-on-unfuzzy' is `nil'.

   The initial value of `po-auto-fuzzy-on-edit' is `nil'.  However, if
the variable `po-auto-fuzzy-on-edit' is set to `t', any entry edited
through the `<RET>' command is marked fuzzy, as a way to ensure some
kind of double check, later.  In this case, the usual paradigm is that
an entry becomes fuzzy (if not already) whenever the translator
modifies it.  If she is satisfied with the translation, she then uses
`<TAB>' to pick another entry to work on, clearing the fuzzy attribute
on the same blow.  If she is not satisfied yet, she merely uses `<SPC>'
to chase another entry, leaving the entry fuzzy.

   The translator may also use the `<DEL>' command
(`po-fade-out-entry') over any translated entry to mark it as being
fuzzy, when she wants to easily leave a trace she wants to later return
working at this entry.

   Also, when time comes to quit working on a PO file buffer with the
`q' command, the translator is asked for confirmation, if fuzzy string
still exists.


File: gettext.info,  Node: Untranslated Entries,  Next: Obsolete Entries,  Prev: Fuzzy Entries,  Up: Updating

Untranslated Entries
====================

When `xgettext' originally creates a PO file, unless told otherwise, it
initializes the `msgid' field with the untranslated string, and leaves
the `msgstr' string to be empty.  Such entries, having an empty
translation, are said to be "untranslated" entries.  Later, when the
programmer slightly modifies some string right in the program, this
change is later reflected in the PO file by the appearance of a new
untranslated entry for the modified string.

   The usual commands moving from entry to entry consider untranslated
entries on the same level as active entries.  Untranslated entries are
easily recognizable by the fact they end with `msgstr ""'.

   The work of the translator might be (quite naively) seen as the
process of seeking for an untranslated entry, editing a translation for
it, and repeating these actions until no untranslated entries remain.
Some commands are more specifically related to untranslated entry
processing.

`u'
     Find the next untranslated entry (`po-next-untranslated-entry').

`U'
     Find the previous untranslated entry
     (`po-previous-untransted-entry').

`k'
     Turn the current entry into an untranslated one (`po-kill-msgstr').


   The commands `u' (`po-next-untranslated-entry') and `U'
(`po-previous-untransted-entry') move forwards or backwards, chasing
for an untranslated entry.  If none is found, the search is extended
and wraps around in the PO file buffer.

   An entry can be turned back into an untranslated entry by merely
emptying its translation, using the command `k' (`po-kill-msgstr').
*Note Modifying Translations::.

   Also, when time comes to quit working on a PO file buffer with the
`q' command, the translator is asked for confirmation, if some
untranslated string still exists.


File: gettext.info,  Node: Obsolete Entries,  Next: Modifying Translations,  Prev: Untranslated Entries,  Up: Updating

Obsolete Entries
================

By "obsolete" PO file entries, we mean those entries which are
commented out, usually by `msgmerge' when it found that the translation
is not needed anymore by the package being localized.

   The usual commands moving from entry to entry consider obsolete
entries on the same level as active entries.  Obsolete entries are
easily recognizable by the fact that all their lines start with `#',
even those lines containing `msgid' or `msgstr'.

   Commands exist for emptying the translation or reinitializing it to
the original untranslated string.  Commands interfacing with the kill
ring may force some previously saved text into the translation.  The
user may interactively edit the translation.  All these commands may
apply to obsolete entries, carefully leaving the entry obsolete after
the fact.

   Moreover, some commands are more specifically related to obsolete
entry processing.

`o'
     Find the next obsolete entry (`po-next-obsolete-entry').

`O'
     Find the previous obsolete entry (`po-previous-obsolete-entry').

`<DEL>'
     Make an active entry obsolete, or zap out an obsolete entry
     (`po-fade-out-entry').


   The commands `o' (`po-next-obsolete-entry') and `O'
(`po-previous-obsolete-entry') move forwards or backwards, chasing for
an obsolete entry.  If none is found, the search is extended and wraps
around in the PO file buffer.

   PO mode does not provide ways for un-commenting an obsolete entry
and making it active, because this would reintroduce an original
untranslated string which does not correspond to any marked string in
the program sources.  This goes with the philosophy of never
introducing useless `msgid' values.

   However, it is possible to comment out an active entry, so making it
obsolete.  GNU `gettext' utilities will later react to the
disappearance of a translation by using the untranslated string.  The
command `<DEL>' (`po-fade-out-entry') pushes the current entry a little
further towards annihilation.  If the entry is active (it is a
translated entry), then it is first made fuzzy.  If it is already fuzzy,
then the entry is merely commented out, with confirmation.  If the entry
is already obsolete, then it is completely deleted from the PO file.
It is easy to recycle the translation so deleted into some other PO file
entry, usually one which is untranslated.  *Note Modifying
Translations::.

   Here is a quite interesting problem to solve for later development of
PO mode, for those nights you are not sleepy.  The idea would be that
PO mode might become bright enough, one of these days, to make good
guesses at retrieving the most probable candidate, among all obsolete
entries, for initializing the translation of a newly appeared string.
I think it might be a quite hard problem to do this algorithmically, as
we have to develop good and efficient measures of string similarity.
Right now, PO mode completely lets the decision to the translator, when
the time comes to find the adequate obsolete translation, it merely
tries to provide handy tools for helping her to do so.


File: gettext.info,  Node: Modifying Translations,  Next: Modifying Comments,  Prev: Obsolete Entries,  Up: Updating

Modifying Translations
======================

PO mode prevents direct modification of the PO file, by the usual means
Emacs gives for altering a buffer's contents.  By doing so, it pretends
helping the translator to avoid little clerical errors about the
overall file format, or the proper quoting of strings, as those errors
would be easily made.  Other kinds of errors are still possible, but
some may be caught and diagnosed by the batch validation process, which
the translator may always trigger by the `V' command.  For all other
errors, the translator has to rely on her own judgment, and also on the
linguistic reports submitted to her by the users of the translated
package, having the same mother tongue.

   When the time comes to create a translation, correct an error
diagnosed mechanically or reported by a user, the translators have to
resort to using the following commands for modifying the translations.

`<RET>'
     Interactively edit the translation (`po-edit-msgstr').

`<LFD>'
`C-j'
     Reinitialize the translation with the original, untranslated string
     (`po-msgid-to-msgstr').

`k'
     Save the translation on the kill ring, and delete it
     (`po-kill-msgstr').

`w'
     Save the translation on the kill ring, without deleting it
     (`po-kill-ring-save-msgstr').

`y'
     Replace the translation, taking the new from the kill ring
     (`po-yank-msgstr').


   The command `<RET>' (`po-edit-msgstr') opens a new Emacs window
meant to edit in a new translation, or to modify an already existing
translation.  The new window contains a copy of the translation taken
from the current PO file entry, all ready for edition, expunged of all
quoting marks, fully modifiable and with the complete extent of Emacs
modifying commands.  When the translator is done with her
modifications, she may use `C-c C-c' to close the subedit window with
the automatically requoted results, or `C-c C-k' to abort her
modifications.  *Note Subedit::, for more information.

   The command `<LFD>' (`po-msgid-to-msgstr') initializes, or
reinitializes the translation with the original string.  This command is
normally used when the translator wants to redo a fresh translation of
the original string, disregarding any previous work.

   It is possible to arrange so, whenever editing an untranslated
entry, the `<LFD>' command be automatically executed.  If you set
`po-auto-edit-with-msgid' to `t', the translation gets initialised with
the original string, in case none exists already.  The default value
for `po-auto-edit-with-msgid' is `nil'.

   In fact, whether it is best to start a translation with an empty
string, or rather with a copy of the original string, is a matter of
taste or habit.  Sometimes, the source language and the target language
are so different that is simply best to start writing on an empty page.
At other times, the source and target languages are so close that it
would be a waste to retype a number of words already being written in
the original string.  A translator may also like having the original
string right under her eyes, as she will progressively overwrite the
original text with the translation, even if this requires some extra
editing work to get rid of the original.

   The command `k' (`po-kill-msgstr') merely empties the translation
string, so turning the entry into an untranslated one.  But while doing
so, its previous contents is put apart in a special place, known as the
kill ring.  The command `w' (`po-kill-ring-save-msgstr') has also the
effect of taking a copy of the translation onto the kill ring, but it
otherwise leaves the entry alone, and does _not_ remove the translation
from the entry.  Both commands use exactly the Emacs kill ring, which
is shared between buffers, and which is well known already to Emacs
lovers.

   The translator may use `k' or `w' many times in the course of her
work, as the kill ring may hold several saved translations.  From the
kill ring, strings may later be reinserted in various Emacs buffers.
In particular, the kill ring may be used for moving translation strings
between different entries of a single PO file buffer, or if the
translator is handling many such buffers at once, even between PO files.

   To facilitate exchanges with buffers which are not in PO mode, the
translation string put on the kill ring by the `k' command is fully
unquoted before being saved: external quotes are removed, multi-line
strings are concatenated, and backslash escaped sequences are turned
into their corresponding characters.  In the special case of obsolete
entries, the translation is also uncommented prior to saving.

   The command `y' (`po-yank-msgstr') completely replaces the
translation of the current entry by a string taken from the kill ring.
Following Emacs terminology, we then say that the replacement string is
"yanked" into the PO file buffer.  *Note Yanking: (emacs)Yanking.  The
first time `y' is used, the translation receives the value of the most
recent addition to the kill ring.  If `y' is typed once again,
immediately, without intervening keystrokes, the translation just
inserted is taken away and replaced by the second most recent addition
to the kill ring.  By repeating `y' many times in a row, the translator
may travel along the kill ring for saved strings, until she finds the
string she really wanted.

   When a string is yanked into a PO file entry, it is fully and
automatically requoted for complying with the format PO files should
have.  Further, if the entry is obsolete, PO mode then appropriately
push the inserted string inside comments.  Once again, translators
should not burden themselves with quoting considerations besides, of
course, the necessity of the translated string itself respective to the
program using it.

   Note that `k' or `w' are not the only commands pushing strings on
the kill ring, as almost any PO mode command replacing translation
strings (or the translator comments) automatically saves the old string
on the kill ring.  The main exceptions to this general rule are the
yanking commands themselves.

   To better illustrate the operation of killing and yanking, let's use
an actual example, taken from a common situation.  When the programmer
slightly modifies some string right in the program, his change is later
reflected in the PO file by the appearance of a new untranslated entry
for the modified string, and the fact that the entry translating the
original or unmodified string becomes obsolete.  In many cases, the
translator might spare herself some work by retrieving the unmodified
translation from the obsolete entry, then initializing the untranslated
entry `msgstr' field with this retrieved translation.  Once this done,
the obsolete entry is not wanted anymore, and may be safely deleted.

   When the translator finds an untranslated entry and suspects that a
slight variant of the translation exists, she immediately uses `m' to
mark the current entry location, then starts chasing obsolete entries
with `o', hoping to find some translation corresponding to the
unmodified string.  Once found, she uses the `<DEL>' command for
deleting the obsolete entry, knowing that `<DEL>' also _kills_ the
translation, that is, pushes the translation on the kill ring.  Then,
`r' returns to the initial untranslated entry, and `y' then _yanks_ the
saved translation right into the `msgstr' field.  The translator is
then free to use `<RET>' for fine tuning the translation contents, and
maybe to later use `u', then `m' again, for going on with the next
untranslated string.

   When some sequence of keys has to be typed over and over again, the
translator may find it useful to become better acquainted with the Emacs
capability of learning these sequences and playing them back under
request.  *Note Keyboard Macros: (emacs)Keyboard Macros.


File: gettext.info,  Node: Modifying Comments,  Next: Subedit,  Prev: Modifying Translations,  Up: Updating

Modifying Comments
==================

Any translation work done seriously will raise many linguistic
difficulties, for which decisions have to be made, and the choices
further documented.  These documents may be saved within the PO file in
form of translator comments, which the translator is free to create,
delete, or modify at will.  These comments may be useful to herself
when she returns to this PO file after a while.

   Comments not having whitespace after the initial `#', for example,
those beginning with `#.' or `#:', are _not_ translator comments, they
are exclusively created by other `gettext' tools.  So, the commands
below will never alter such system added comments, they are not meant
for the translator to modify.  *Note PO Files::.

   The following commands are somewhat similar to those modifying
translations, so the general indications given for those apply here.
*Note Modifying Translations::.

`#'
     Interactively edit the translator comments (`po-edit-comment').

`K'
     Save the translator comments on the kill ring, and delete it
     (`po-kill-comment').

`W'
     Save the translator comments on the kill ring, without deleting it
     (`po-kill-ring-save-comment').

`Y'
     Replace the translator comments, taking the new from the kill ring
     (`po-yank-comment').


   These commands parallel PO mode commands for modifying the
translation strings, and behave much the same way as they do, except
that they handle this part of PO file comments meant for translator
usage, rather than the translation strings.  So, if the descriptions
given below are slightly succinct, it is because the full details have
already been given.  *Note Modifying Translations::.

   The command `#' (`po-edit-comment') opens a new Emacs window
containing a copy of the translator comments on the current PO file
entry.  If there are no such comments, PO mode understands that the
translator wants to add a comment to the entry, and she is presented
with an empty screen.  Comment marks (`#') and the space following them
are automatically removed before edition, and reinstated after.  For
translator comments pertaining to obsolete entries, the uncommenting
and recommenting operations are done twice.  Once in the editing
window, the keys `C-c C-c' allow the translator to tell she is finished
with editing the comment.  *Note Subedit::, for further details.

   Functions found on `po-subedit-mode-hook', if any, are executed after
the string has been inserted in the edit buffer.

   The command `K' (`po-kill-comment') gets rid of all translator
comments, while saving those comments on the kill ring.  The command
`W' (`po-kill-ring-save-comment') takes a copy of the translator
comments on the kill ring, but leaves them undisturbed in the current
entry.  The command `Y' (`po-yank-comment') completely replaces the
translator comments by a string taken at the front of the kill ring.
When this command is immediately repeated, the comments just inserted
are withdrawn, and replaced by other strings taken along the kill ring.

   On the kill ring, all strings have the same nature.  There is no
distinction between _translation_ strings and _translator comments_
strings.  So, for example, let's presume the translator has just
finished editing a translation, and wants to create a new translator
comment to document why the previous translation was not good, just to
remember what was the problem.  Foreseeing that she will do that in her
documentation, the translator may want to quote the previous
translation in her translator comments.  To do so, she may initialize
the translator comments with the previous translation, still at the
head of the kill ring.  Because editing already pushed the previous
translation on the kill ring, she merely has to type `M-w' prior to
`#', and the previous translation will be right there, all ready for
being introduced by some explanatory text.

   On the other hand, presume there are some translator comments already
and that the translator wants to add to those comments, instead of
wholly replacing them.  Then, she should edit the comment right away
with `#'.  Once inside the editing window, she can use the regular
Emacs commands `C-y' (`yank') and `M-y' (`yank-pop') to get the
previous translation where she likes.


File: gettext.info,  Node: Subedit,  Next: C Sources Context,  Prev: Modifying Comments,  Up: Updating

Details of Sub Edition
======================

The PO subedit minor mode has a few peculiarities worth being described
in fuller detail.  It installs a few commands over the usual editing set
of Emacs, which are described below.

`C-c C-c'
     Complete edition (`po-subedit-exit').

`C-c C-k'
     Abort edition (`po-subedit-abort').

`C-c C-a'
     Consult auxiliary PO files (`po-subedit-cycle-auxiliary').


   The window's contents represents a translation for a given message,
or a translator comment.  The translator may modify this window to her
heart's content.  Once this is done, the command `C-c C-c'
(`po-subedit-exit') may be used to return the edited translation into
the PO file, replacing the original translation, even if it moved out of
sight or if buffers were switched.

   If the translator becomes unsatisfied with her translation or
comment, to the extent she prefers keeping what was existent prior to
the `<RET>' or `#' command, she may use the command `C-c C-k'
(`po-subedit-abort') to merely get rid of edition, while preserving the
original translation or comment.  Another way would be for her to exit
normally with `C-c C-c', then type `U' once for undoing the whole
effect of last edition.

   The command `C-c C-a' (`po-subedit-cycle-auxiliary') allows for
glancing through translations already achieved in other languages,
directly while editing the current translation.  This may be quite
convenient when the translator is fluent at many languages, but of
course, only makes sense when such completed auxiliary PO files are
already available to her (*note Auxiliary::).

   Functions found on `po-subedit-mode-hook', if any, are executed after
the string has been inserted in the edit buffer.

   While editing her translation, the translator should pay attention
to not inserting unwanted `<RET>' (newline) characters at the end of
the translated string if those are not meant to be there, or to removing
such characters when they are required.  Since these characters are not
visible in the editing buffer, they are easily introduced by mistake.
To help her, `<RET>' automatically puts the character `<' at the end of
the string being edited, but this `<' is not really part of the string.
On exiting the editing window with `C-c C-c', PO mode automatically
removes such `<' and all whitespace added after it.  If the translator
adds characters after the terminating `<', it looses its delimiting
property and integrally becomes part of the string.  If she removes the
delimiting `<', then the edited string is taken _as is_, with all
trailing newlines, even if invisible.  Also, if the translated string
ought to end itself with a genuine `<', then the delimiting `<' may not
be removed; so the string should appear, in the editing window, as
ending with two `<' in a row.

   When a translation (or a comment) is being edited, the translator
may move the cursor back into the PO file buffer and freely move to
other entries, browsing at will.  If, with an edition pending, the
translator wanders in the PO file buffer, she may decide to start
modifying another entry.  Each entry being edited has its own subedit
buffer.  It is possible to simultaneously edit the translation _and_
the comment of a single entry, or to edit entries in different PO
files, all at once.  Typing `<RET>' on a field already being edited
merely resumes that particular edit.  Yet, the translator should better
be comfortable at handling many Emacs windows!

   Pending subedits may be completed or aborted in any order, regardless
of how or when they were started.  When many subedits are pending and
the translator asks for quitting the PO file (with the `q' command),
subedits are automatically resumed one at a time, so she may decide for
each of them.


File: gettext.info,  Node: C Sources Context,  Next: Auxiliary,  Prev: Subedit,  Up: Updating

C Sources Context
=================

PO mode is particularly powerful when used with PO files created
through GNU `gettext' utilities, as those utilities insert special
comments in the PO files they generate.  Some of these special comments
relate the PO file entry to exactly where the untranslated string
appears in the program sources.

   When the translator gets to an untranslated entry, she is fairly
often faced with an original string which is not as informative as it
normally should be, being succinct, cryptic, or otherwise ambiguous.
Before choosing how to translate the string, she needs to understand
better what the string really means and how tight the translation has
to be.  Most of the time, when problems arise, the only way left to make
her judgment is looking at the true program sources from where this
string originated, searching for surrounding comments the programmer
might have put in there, and looking around for helping clues of _any_
kind.

   Surely, when looking at program sources, the translator will receive
more help if she is a fluent programmer.  However, even if she is not
versed in programming and feels a little lost in C code, the translator
should not be shy at taking a look, once in a while.  It is most
probable that she will still be able to find some of the hints she
needs.  She will learn quickly to not feel uncomfortable in program
code, paying more attention to programmer's comments, variable and
function names (if he dared choosing them well), and overall
organization, than to the program code itself.

   The following commands are meant to help the translator at getting
program source context for a PO file entry.

`s'
     Resume the display of a program source context, or cycle through
     them (`po-cycle-source-reference').

`M-s'
     Display of a program source context selected by menu
     (`po-select-source-reference').

`S'
     Add a directory to the search path for source files
     (`po-consider-source-path').

`M-S'
     Delete a directory from the search path for source files
     (`po-ignore-source-path').


   The commands `s' (`po-cycle-source-reference') and `M-s'
(`po-select-source-reference') both open another window displaying some
source program file, and already positioned in such a way that it shows
an actual use of the string to be translated.  By doing so, the command
gives source program context for the string.  But if the entry has no
source context references, or if all references are unresolved along
the search path for program sources, then the command diagnoses this as
an error.

   Even if `s' (or `M-s') opens a new window, the cursor stays in the
PO file window.  If the translator really wants to get into the program
source window, she ought to do it explicitly, maybe by using command
`O'.

   When `s' is typed for the first time, or for a PO file entry which
is different of the last one used for getting source context, then the
command reacts by giving the first context available for this entry, if
any.  If some context has already been recently displayed for the
current PO file entry, and the translator wandered off to do other
things, typing `s' again will merely resume, in another window, the
context last displayed.  In particular, if the translator moved the
cursor away from the context in the source file, the command will bring
the cursor back to the context.  By using `s' many times in a row, with
no other commands intervening, PO mode will cycle to the next available
contexts for this particular entry, getting back to the first context
once the last has been shown.

   The command `M-s' behaves differently.  Instead of cycling through
references, it lets the translator choose a particular reference among
many, and displays that reference.  It is best used with completion, if
the translator types `<TAB>' immediately after `M-s', in response to
the question, she will be offered a menu of all possible references, as
a reminder of which are the acceptable answers.  This command is useful
only where there are really many contexts available for a single string
to translate.

   Program source files are usually found relative to where the PO file
stands.  As a special provision, when this fails, the file is also
looked for, but relative to the directory immediately above it.  Those
two cases take proper care of most PO files.  However, it might happen
that a PO file has been moved, or is edited in a different place than
its normal location.  When this happens, the translator should tell PO
mode in which directory normally sits the genuine PO file.  Many such
directories may be specified, and all together, they constitute what is
called the "search path" for program sources.  The command `S'
(`po-consider-source-path') is used to interactively enter a new
directory at the front of the search path, and the command `M-S'
(`po-ignore-source-path') is used to select, with completion, one of
the directories she does not want anymore on the search path.


File: gettext.info,  Node: Auxiliary,  Next: Compendium,  Prev: C Sources Context,  Up: Updating

Consulting Auxiliary PO Files
=============================

PO mode is able to help the knowledgeable translator, being fluent in
many languages, at taking advantage of translations already achieved in
other languages she just happens to know.  It provides these other
language translations as additional context for her own work.  Moreover,
it has features to ease the production of translations for many
languages at once, for translators preferring to work in this way.

   An "auxiliary" PO file is an existing PO file meant for the same
package the translator is working on, but targeted to a different mother
tongue language.  Commands exist for declaring and handling auxiliary
PO files, and also for showing contexts for the entry under work.

   Here are the auxiliary file commands available in PO mode.

`a'
     Seek auxiliary files for another translation for the same entry
     (`po-cycle-auxiliary').

`C-c C-a'
     Switch to a particular auxiliary file (`po-select-auxiliary').

`A'
     Declare this PO file as an auxiliary file
     (`po-consider-as-auxiliary').

`M-A'
     Remove this PO file from the list of auxiliary files
     (`po-ignore-as-auxiliary').


   Command `A' (`po-consider-as-auxiliary') adds the current PO file to
the list of auxiliary files, while command `M-A'
(`po-ignore-as-auxiliary' just removes it.

   The command `a' (`po-cycle-auxiliary') seeks all auxiliary PO files,
round-robin, searching for a translated entry in some other language
having an `msgid' field identical as the one for the current entry.
The found PO file, if any, takes the place of the current PO file in
the display (its window gets on top).  Before doing so, the current PO
file is also made into an auxiliary file, if not already.  So, `a' in
this newly displayed PO file will seek another PO file, and so on, so
repeating `a' will eventually yield back the original PO file.

   The command `C-c C-a' (`po-select-auxiliary') asks the translator
for her choice of a particular auxiliary file, with completion, and
then switches to that selected PO file.  The command also checks if the
selected file has an `msgid' field identical as the one for the current
entry, and if yes, this entry becomes current.  Otherwise, the cursor
of the selected file is left undisturbed.

   For all this to work fully, auxiliary PO files will have to be
normalized, in that way that `msgid' fields should be written _exactly_
the same way.  It is possible to write `msgid' fields in various ways
for representing the same string, different writing would break the
proper behaviour of the auxiliary file commands of PO mode.  This is not
expected to be much a problem in practice, as most existing PO files
have their `msgid' entries written by the same GNU `gettext' tools.

   However, PO files initially created by PO mode itself, while marking
strings in source files, are normalised differently.  So are PO files
resulting of the the `M-x normalize' command.  Until these
discrepancies between PO mode and other GNU `gettext' tools get fully
resolved, the translator should stay aware of normalisation issues.


File: gettext.info,  Node: Compendium,  Prev: Auxiliary,  Up: Updating

Using Translation Compendia
===========================

A "compendium" is a special PO file containing a set of translations
recurring in many different packages.  The translator can use gettext
tools to build a new compendium, to add entries to her compendium, and
to initialize untranslated entries, or to update already translated
entries, from translations kept in the compendium.

* Menu:

* Creating Compendia::          Merging translations for later use
* Using Compendia::             Using older translations if they fit


File: gettext.info,  Node: Creating Compendia,  Next: Using Compendia,  Prev: Compendium,  Up: Compendium

Creating Compendia
------------------

Basically every PO file consisting of translated entries only can be
declared as a valid compendium.  Often the translator wants to have
special compendia; let's consider two cases: `concatenating PO files'
and `extracting a message subset from a PO file'.

Concatenate PO Files
....................

To concatenate several valid PO files into one compendium file you can
use `msgcomm' or `msgcat' (the latter preferred):

     msgcat -o compendium.po file1.po file2.po

   By default, `msgcat' will accumulate divergent translations for the
same string.  Those occurences will be marked as `fuzzy' and highly
visible decorated; calling `msgcat' on `file1.po':

     #: src/hello.c:200
     #, c-format
     msgid "Report bugs to <%s>.\n"
     msgstr "Comunicar `bugs' a <%s>.\n"

and `file2.po':

     #: src/bye.c:100
     #, c-format
     msgid "Report bugs to <%s>.\n"
     msgstr "Comunicar \"bugs\" a <%s>.\n"

will result in:

     #: src/hello.c:200 src/bye.c:100
     #, fuzzy, c-format
     msgid "Report bugs to <%s>.\n"
     msgstr ""
     "#-#-#-#-#  file1.po  #-#-#-#-#\n"
     "Comunicar `bugs' a <%s>.\n"
     "#-#-#-#-#  file2.po  #-#-#-#-#\n"
     "Comunicar \"bugs\" a <%s>.\n"

The translator will have to resolve this "conflict" manually; she has
to decide whether the first or the second version is appropriate (or
provide a new translation), to delete the "marker lines", and finally
to remove the `fuzzy' mark.

   If the translator knows in advance the first found translation of a
message is always the best translation she can make use to the
`--use-first' switch:

     msgcat --use-first -o compendium.po file1.po file2.po

   A good compendium file must not contain `fuzzy' or untranslated
entries.  If input files are "dirty" you must preprocess the input
files or postprocess the result using `msgattrib --translated
--no-fuzzy'.

Extract a Message Subset from a PO File
.......................................

Nobody wants to translate the same messages again and again; thus you
may wish to have a compendium file containing `getopt.c' messages.

   To extract a message subset (e.g., all `getopt.c' messages) from an
existing PO file into one compendium file you can use `msggrep':

     msggrep --location src/getopt.c -o compendium.po file.po


File: gettext.info,  Node: Using Compendia,  Prev: Creating Compendia,  Up: Compendium

Using Compendia
---------------

You can use a compendium file to initialize a translation from scratch
or to update an already existing translation.

Initialize a New Translation File
.................................

Since a PO file with translations does not exist the translator can
merely use `/dev/null' to fake the "old" translation file.

     msgmerge --compendium compendium.po -o file.po /dev/null file.pot

Update an Existing Translation File
...................................

Concatenate the compendium file(s) and the existing PO, merge the
result with the POT file and remove the obsolete entries (optional,
here done using `sed'):

     msgcat --use-first -o update.po compendium1.po compendium2.po file.po
     msgmerge update.po file.pot | sed -e '/^#~/d' > file.po


File: gettext.info,  Node: Manipulating,  Next: Binaries,  Prev: Updating,  Up: Top

Manipulating PO Files
*********************

Sometimes it is necessary to manipulate PO files in a way that is better
performed automatically than by hand.  GNU `gettext' includes a
complete set of tools for this purpose.

   When merging two packages into a single package, the resulting POT
file will be the concatenation of the two packages' POT files.  Thus the
maintainer must concatenate the two existing package translations into
a single translation catalog, for each language.  This is best performed
using `msgcat'.  It is then the translators' duty to deal with any
possible conflicts that arose during the merge.

   When a translator takes over the translation job from another
translator, but she uses a different character encoding in her locale,
she will convert the catalog to her character encoding.  This is best
done through the `msgconv' program.

   When a maintainer takes a source file with tagged messages from
another package, he should also take the existing translations for this
source file (and not let the translators do the same job twice).  One
way to do this is through `msggrep', another is to create a POT file for
that source file and use `msgmerge'.

   When a translator wants to adjust some translation catalog for a
special dialect or orthography -- for example, German as written in
Switzerland versus German as written in Germany -- she needs to apply
some text processing to every message in the catalog.  The tool for
doing this is `msgfilter'.

   Another use of `msgfilter' is to produce approximately the POT file
for which a given PO file was made.  This can be done through a filter
command like `msgfilter sed -e d | sed -e '/^# /d''.  Note that the
original POT file may have had different comments and different plural
message counts, that's why it's better to use the original POT file if
available.

   When a translator wants to check her translations, for example
according to orthography rules or using a non-interactive spell
checker, she can do so using the `msgexec' program.

   When third party tools create PO or POT files, sometimes duplicates
cannot be avoided.  But the GNU `gettext' tools give an error when they
encounter duplicate msgids in the same file and in the same domain.  To
merge duplicates, the `msguniq' program can be used.

   `msgcomm' is a more general tool for keeping or throwing away
duplicates, occurring in different files.

   `msgcmp' can be used to check whether a translation catalog is
completely translated.

   `msgattrib' can be used to select and extract only the fuzzy or
untranslated messages of a translation catalog.

   `msgen' is useful as a first step for preparing English translation
catalogs.  It copies each message's msgid to its msgstr.

   Finally, for those applications where all these various programs are
not sufficient, a library `libgettextpo' is provided that can be used to
write other specialized programs that process PO files.

* Menu:

* msgcat Invocation::           Invoking the `msgcat' Program
* msgconv Invocation::          Invoking the `msgconv' Program
* msggrep Invocation::          Invoking the `msggrep' Program
* msgfilter Invocation::        Invoking the `msgfilter' Program
* msguniq Invocation::          Invoking the `msguniq' Program
* msgcomm Invocation::          Invoking the `msgcomm' Program
* msgcmp Invocation::           Invoking the `msgcmp' Program
* msgattrib Invocation::        Invoking the `msgattrib' Program
* msgen Invocation::            Invoking the `msgen' Program
* msgexec Invocation::          Invoking the `msgexec' Program
* libgettextpo::                Writing your own programs that process PO files


File: gettext.info,  Node: msgcat Invocation,  Next: msgconv Invocation,  Prev: Manipulating,  Up: Manipulating

Invoking the `msgcat' Program
=============================

     msgcat [OPTION] [INPUTFILE]...

   The `msgcat' program concatenates and merges the specified PO files.
It finds messages which are common to two or more of the specified PO
files.  By using the `--more-than' option, greater commonality may be
requested before messages are printed.  Conversely, the `--less-than'
option may be used to specify less commonality before messages are
printed (i.e.  `--less-than=2' will only print the unique messages).
Translations, comments and extract comments will be cumulated, except
that if `--use-first' is specified, they will be taken from the first
PO file to define them.  File positions from all PO files will be
cumulated.

Input file location
-------------------

`INPUTFILE ...'
     Input files.

`-f FILE'
`--files-from=FILE'
     Read the names of the input files from FILE instead of getting
     them from the command line.

`-D DIRECTORY'
`--directory=DIRECTORY'
     Add DIRECTORY to the list of directories.  Source files are
     searched relative to this list of directories.  The resulting `.po'
     file will be written relative to the current directory, though.


   If INPUTFILE is `-', standard input is read.

Output file location
--------------------

`-o FILE'
`--output-file=FILE'
     Write output to specified file.


   The results are written to standard output if no output file is
specified or if it is `-'.

Message selection
-----------------

`-< NUMBER'
`--less-than=NUMBER'
     Print messages with less than NUMBER definitions, defaults to
     infinite if not set.

`-> NUMBER'
`--more-than=NUMBER'
     Print messages with more than NUMBER definitions, defaults to 0 if
     not set.

`-u'
`--unique'
     Shorthand for `--less-than=2'.  Requests that only unique messages
     be printed.


Input file syntax
-----------------

`-P'
`--properties-input'
     Assume the input files are Java ResourceBundles in Java
     `.properties' syntax, not in PO file syntax.

`--stringtable-input'
     Assume the input files are NeXTstep/GNUstep localized resource
     files in `.strings' syntax, not in PO file syntax.


Output details
--------------

`-t'
`--to-code=NAME'
     Specify encoding for output.

`--use-first'
     Use first available translation for each message.  Don't merge
     several translations into one.

`--force-po'
     Always write an output file even if it contains no message.

`-i'
`--indent'
     Write the .po file using indented style.

`--no-location'
     Do not write `#: FILENAME:LINE' lines.

`-n'
`--add-location'
     Generate `#: FILENAME:LINE' lines (default).

`--strict'
     Write out a strict Uniforum conforming PO file.  Note that this
     Uniforum format should be avoided because it doesn't support the
     GNU extensions.

`-p'
`--properties-output'
     Write out a Java ResourceBundle in Java `.properties' syntax.  Note
     that this file format doesn't support plural forms and silently
     drops obsolete messages.

`--stringtable-output'
     Write out a NeXTstep/GNUstep localized resource file in `.strings'
     syntax.  Note that this file format doesn't support plural forms.

`-w NUMBER'
`--width=NUMBER'
     Set the output page width.  Long strings in the output files will
     be split across multiple lines in order to ensure that each line's
     width (= number of screen columns) is less or equal to the given
     NUMBER.

`--no-wrap'
     Do not break long message lines.  Message lines whose width
     exceeds the output page width will not be split into several
     lines.  Only file reference lines which are wider than the output
     page width will be split.

`-s'
`--sort-output'
     Generate sorted output.  Note that using this option makes it much
     harder for the translator to understand each message's context.

`-F'
`--sort-by-file'
     Sort output by file location.


Informative output
------------------

`-h'
`--help'
     Display this help and exit.

`-V'
`--version'
     Output version information and exit.



File: gettext.info,  Node: msgconv Invocation,  Next: msggrep Invocation,  Prev: msgcat Invocation,  Up: Manipulating

Invoking the `msgconv' Program
==============================

     msgconv [OPTION] [INPUTFILE]

   The `msgconv' program converts a translation catalog to a different
character encoding.

Input file location
-------------------

`INPUTFILE'
     Input PO file.

`-D DIRECTORY'
`--directory=DIRECTORY'
     Add DIRECTORY to the list of directories.  Source files are
     searched relative to this list of directories.  The resulting `.po'
     file will be written relative to the current directory, though.


   If no INPUTFILE is given or if it is `-', standard input is read.

Output file location
--------------------

`-o FILE'
`--output-file=FILE'
     Write output to specified file.


   The results are written to standard output if no output file is
specified or if it is `-'.

Conversion target
-----------------

`-t'
`--to-code=NAME'
     Specify encoding for output.


   The default encoding is the current locale's encoding.

Input file syntax
-----------------

`-P'
`--properties-input'
     Assume the input file is a Java ResourceBundle in Java
     `.properties' syntax, not in PO file syntax.

`--stringtable-input'
     Assume the input file is a NeXTstep/GNUstep localized resource
     file in `.strings' syntax, not in PO file syntax.


Output details
--------------

`--force-po'
     Always write an output file even if it contains no message.

`-i'
`--indent'
     Write the .po file using indented style.

`--no-location'
     Do not write `#: FILENAME:LINE' lines.

`--add-location'
     Generate `#: FILENAME:LINE' lines (default).

`--strict'
     Write out a strict Uniforum conforming PO file.  Note that this
     Uniforum format should be avoided because it doesn't support the
     GNU extensions.

`-p'
`--properties-output'
     Write out a Java ResourceBundle in Java `.properties' syntax.  Note
     that this file format doesn't support plural forms and silently
     drops obsolete messages.

`--stringtable-output'
     Write out a NeXTstep/GNUstep localized resource file in `.strings'
     syntax.  Note that this file format doesn't support plural forms.

`-w NUMBER'
`--width=NUMBER'
     Set the output page width.  Long strings in the output files will
     be split across multiple lines in order to ensure that each line's
     width (= number of screen columns) is less or equal to the given
     NUMBER.

`--no-wrap'
     Do not break long message lines.  Message lines whose width
     exceeds the output page width will not be split into several
     lines.  Only file reference lines which are wider than the output
     page width will be split.

`-s'
`--sort-output'
     Generate sorted output.  Note that using this option makes it much
     harder for the translator to understand each message's context.

`-F'
`--sort-by-file'
     Sort output by file location.


Informative output
------------------

`-h'
`--help'
     Display this help and exit.

`-V'
`--version'
     Output version information and exit.



File: gettext.info,  Node: msggrep Invocation,  Next: msgfilter Invocation,  Prev: msgconv Invocation,  Up: Manipulating

Invoking the `msggrep' Program
==============================

     msggrep [OPTION] [INPUTFILE]

   The `msggrep' program extracts all messages of a translation catalog
that match a given pattern or belong to some given source files.

Input file location
-------------------

`INPUTFILE'
     Input PO file.

`-D DIRECTORY'
`--directory=DIRECTORY'
     Add DIRECTORY to the list of directories.  Source files are
     searched relative to this list of directories.  The resulting `.po'
     file will be written relative to the current directory, though.


   If no INPUTFILE is given or if it is `-', standard input is read.

Output file location
--------------------

`-o FILE'
`--output-file=FILE'
     Write output to specified file.


   The results are written to standard output if no output file is
specified or if it is `-'.

Message selection
-----------------

       [-N SOURCEFILE]... [-M DOMAINNAME]...
       [-K MSGID-PATTERN] [-T MSGSTR-PATTERN] [-C COMMENT-PATTERN]

   A message is selected if
   * it comes from one of the specified source files,

   * or if it comes from one of the specified domains,

   * or if `-K' is given and its key (msgid or msgid_plural) matches
       MSGID-PATTERN,

   * or if `-T' is given and its translation (msgstr) matches
     MSGSTR-PATTERN,

   * or if `-C' is given and the translator's comment matches
     COMMENT-PATTERN.

   When more than one selection criterion is specified, the set of
selected messages is the union of the selected messages of each
criterion.

   MSGID-PATTERN or MSGSTR-PATTERN syntax:
       [-E | -F] [-e PATTERN | -f FILE]...
   PATTERNs are basic regular expressions by default, or extended
regular expressions if -E is given, or fixed strings if -F is given.

`-N SOURCEFILE'
`--location=SOURCEFILE'
     Select messages extracted from SOURCEFILE.  SOURCEFILE can be
     either a literal file name or a wildcard pattern.

`-M DOMAINNAME'
`--domain=DOMAINNAME'
     Select messages belonging to domain DOMAINNAME.

`-K'
`--msgid'
     Start of patterns for the msgid.

`-T'
`--msgstr'
     Start of patterns for the msgstr.

`-C'
`--comment'
     Start of patterns for the translator's comment.

`-E'
`--extended-regexp'
     Specify that PATTERN is an extended regular expression.

`-F'
`--fixed-strings'
     Specify that PATTERN is a set of newline-separated strings.

`-e PATTERN'
`--regexp=PATTERN'
     Use PATTERN as a regular expression.

`-f FILE'
`--file=FILE'
     Obtain PATTERN from FILE.

`-i'
`--ignore-case'
     Ignore case distinctions.


Input file syntax
-----------------

`-P'
`--properties-input'
     Assume the input file is a Java ResourceBundle in Java
     `.properties' syntax, not in PO file syntax.

`--stringtable-input'
     Assume the input file is a NeXTstep/GNUstep localized resource
     file in `.strings' syntax, not in PO file syntax.


Output details
--------------

`--force-po'
     Always write an output file even if it contains no message.

`--indent'
     Write the .po file using indented style.

`--no-location'
     Do not write `#: FILENAME:LINE' lines.

`--add-location'
     Generate `#: FILENAME:LINE' lines (default).

`--strict'
     Write out a strict Uniforum conforming PO file.  Note that this
     Uniforum format should be avoided because it doesn't support the
     GNU extensions.

`-p'
`--properties-output'
     Write out a Java ResourceBundle in Java `.properties' syntax.  Note
     that this file format doesn't support plural forms and silently
     drops obsolete messages.

`--stringtable-output'
     Write out a NeXTstep/GNUstep localized resource file in `.strings'
     syntax.  Note that this file format doesn't support plural forms.

`-w NUMBER'
`--width=NUMBER'
     Set the output page width.  Long strings in the output files will
     be split across multiple lines in order to ensure that each line's
     width (= number of screen columns) is less or equal to the given
     NUMBER.

`--no-wrap'
     Do not break long message lines.  Message lines whose width
     exceeds the output page width will not be split into several
     lines.  Only file reference lines which are wider than the output
     page width will be split.

`--sort-output'
     Generate sorted output.  Note that using this option makes it much
     harder for the translator to understand each message's context.

`--sort-by-file'
     Sort output by file location.


Informative output
------------------

`-h'
`--help'
     Display this help and exit.

`-V'
`--version'
     Output version information and exit.



File: gettext.info,  Node: msgfilter Invocation,  Next: msguniq Invocation,  Prev: msggrep Invocation,  Up: Manipulating

Invoking the `msgfilter' Program
================================

     msgfilter [OPTION] FILTER [FILTER-OPTION]

   The `msgfilter' program applies a filter to all translations of a
translation catalog.

Input file location
-------------------

`-i INPUTFILE'
`--input=INPUTFILE'
     Input PO file.

`-D DIRECTORY'
`--directory=DIRECTORY'
     Add DIRECTORY to the list of directories.  Source files are
     searched relative to this list of directories.  The resulting `.po'
     file will be written relative to the current directory, though.


   If no INPUTFILE is given or if it is `-', standard input is read.

Output file location
--------------------

`-o FILE'
`--output-file=FILE'
     Write output to specified file.


   The results are written to standard output if no output file is
specified or if it is `-'.

The filter
----------

The FILTER can be any program that reads a translation from standard
input and writes a modified translation to standard output.  A
frequently used filter is `sed'.

   Note: It is your responsibility to ensure that the FILTER can cope
with input encoded in the translation catalog's encoding.  If the
FILTER wants input in a particular encoding, you can in a first step
convert the translation catalog to that encoding using the `msgconv'
program, before invoking `msgfilter'.  If the FILTER wants input in the
locale's encoding, but you want to avoid the locale's encoding, then
you can first convert the translation catalog to UTF-8 using the
`msgconv' program and then make `msgfilter' work in an UTF-8 locale, by
using the `LC_ALL' environment variable.

   Note: Most translations in a translation catalog don't end with a
newline character.  For this reason, it is important that the FILTER
recognizes its last input line even if it ends without a newline, and
that it doesn't add an undesired trailing newline at the end.  The `sed'
program on some platforms is known to ignore the last line of input if
it is not terminated with a newline.  You can use GNU `sed' instead; it
does not have this limitation.

Useful FILTER-OPTIONs when the FILTER is `sed'
----------------------------------------------

`-e SCRIPT'
`--expression=SCRIPT'
     Add SCRIPT to the commands to be executed.

`-f SCRIPTFILE'
`--file=SCRIPTFILE'
     Add the contents of SCRIPTFILE to the commands to be executed.

`-n'
`--quiet'
`--silent'
     Suppress automatic printing of pattern space.


Input file syntax
-----------------

`-P'
`--properties-input'
     Assume the input file is a Java ResourceBundle in Java
     `.properties' syntax, not in PO file syntax.

`--stringtable-input'
     Assume the input file is a NeXTstep/GNUstep localized resource
     file in `.strings' syntax, not in PO file syntax.


Output details
--------------

`--force-po'
     Always write an output file even if it contains no message.

`--indent'
     Write the .po file using indented style.

`--keep-header'
     Keep the header entry, i.e. the message with `msgid ""',
     unmodified, instead of filtering it.  By default, the header entry
     is subject to filtering like any other message.

`--no-location'
     Do not write `#: FILENAME:LINE' lines.

`--add-location'
     Generate `#: FILENAME:LINE' lines (default).

`--strict'
     Write out a strict Uniforum conforming PO file.  Note that this
     Uniforum format should be avoided because it doesn't support the
     GNU extensions.

`-p'
`--properties-output'
     Write out a Java ResourceBundle in Java `.properties' syntax.  Note
     that this file format doesn't support plural forms and silently
     drops obsolete messages.

`--stringtable-output'
     Write out a NeXTstep/GNUstep localized resource file in `.strings'
     syntax.  Note that this file format doesn't support plural forms.

`-w NUMBER'
`--width=NUMBER'
     Set the output page width.  Long strings in the output files will
     be split across multiple lines in order to ensure that each line's
     width (= number of screen columns) is less or equal to the given
     NUMBER.

`--no-wrap'
     Do not break long message lines.  Message lines whose width
     exceeds the output page width will not be split into several
     lines.  Only file reference lines which are wider than the output
     page width will be split.

`-s'
`--sort-output'
     Generate sorted output.  Note that using this option makes it much
     harder for the translator to understand each message's context.

`-F'
`--sort-by-file'
     Sort output by file location.


Informative output
------------------

`-h'
`--help'
     Display this help and exit.

`-V'
`--version'
     Output version information and exit.



File: gettext.info,  Node: msguniq Invocation,  Next: msgcomm Invocation,  Prev: msgfilter Invocation,  Up: Manipulating

Invoking the `msguniq' Program
==============================

     msguniq [OPTION] [INPUTFILE]

   The `msguniq' program unifies duplicate translations in a translation
catalog.  It finds duplicate translations of the same message ID.  Such
duplicates are invalid input for other programs like `msgfmt',
`msgmerge' or `msgcat'.  By default, duplicates are merged together.
When using the `--repeated' option, only duplicates are output, and all
other messages are discarded.  Comments and extracted comments will be
cumulated, except that if `--use-first' is specified, they will be
taken from the first translation.  File positions will be cumulated.
When using the `--unique' option, duplicates are discarded.

Input file location
-------------------

`INPUTFILE'
     Input PO file.

`-D DIRECTORY'
`--directory=DIRECTORY'
     Add DIRECTORY to the list of directories.  Source files are
     searched relative to this list of directories.  The resulting `.po'
     file will be written relative to the current directory, though.


   If no INPUTFILE is given or if it is `-', standard input is read.

Output file location
--------------------

`-o FILE'
`--output-file=FILE'
     Write output to specified file.


   The results are written to standard output if no output file is
specified or if it is `-'.

Message selection
-----------------

`-d'
`--repeated'
     Print only duplicates.

`-u'
`--unique'
     Print only unique messages, discard duplicates.


Input file syntax
-----------------

`-P'
`--properties-input'
     Assume the input file is a Java ResourceBundle in Java
     `.properties' syntax, not in PO file syntax.

`--stringtable-input'
     Assume the input file is a NeXTstep/GNUstep localized resource
     file in `.strings' syntax, not in PO file syntax.


Output details
--------------

`-t'
`--to-code=NAME'
     Specify encoding for output.

`--use-first'
     Use first available translation for each message.  Don't merge
     several translations into one.

`--force-po'
     Always write an output file even if it contains no message.

`-i'
`--indent'
     Write the .po file using indented style.

`--no-location'
     Do not write `#: FILENAME:LINE' lines.

`-n'
`--add-location'
     Generate `#: FILENAME:LINE' lines (default).

`--strict'
     Write out a strict Uniforum conforming PO file.  Note that this
     Uniforum format should be avoided because it doesn't support the
     GNU extensions.

`-p'
`--properties-output'
     Write out a Java ResourceBundle in Java `.properties' syntax.  Note
     that this file format doesn't support plural forms and silently
     drops obsolete messages.

`--stringtable-output'
     Write out a NeXTstep/GNUstep localized resource file in `.strings'
     syntax.  Note that this file format doesn't support plural forms.

`-w NUMBER'
`--width=NUMBER'
     Set the output page width.  Long strings in the output files will
     be split across multiple lines in order to ensure that each line's
     width (= number of screen columns) is less or equal to the given
     NUMBER.

`--no-wrap'
     Do not break long message lines.  Message lines whose width
     exceeds the output page width will not be split into several
     lines.  Only file reference lines which are wider than the output
     page width will be split.

`-s'
`--sort-output'
     Generate sorted output.  Note that using this option makes it much
     harder for the translator to understand each message's context.

`-F'
`--sort-by-file'
     Sort output by file location.


Informative output
------------------

`-h'
`--help'
     Display this help and exit.

`-V'
`--version'
     Output version information and exit.



File: gettext.info,  Node: msgcomm Invocation,  Next: msgcmp Invocation,  Prev: msguniq Invocation,  Up: Manipulating

Invoking the `msgcomm' Program
==============================

     msgcomm [OPTION] [INPUTFILE]...

   The `msgcomm' program finds messages which are common to two or more
of the specified PO files.  By using the `--more-than' option, greater
commonality may be requested before messages are printed.  Conversely,
the `--less-than' option may be used to specify less commonality before
messages are printed (i.e.  `--less-than=2' will only print the unique
messages).  Translations, comments and extract comments will be
preserved, but only from the first PO file to define them.  File
positions from all PO files will be cumulated.

Input file location
-------------------

`INPUTFILE ...'
     Input files.

`-f FILE'
`--files-from=FILE'
     Read the names of the input files from FILE instead of getting
     them from the command line.

`-D DIRECTORY'
`--directory=DIRECTORY'
     Add DIRECTORY to the list of directories.  Source files are
     searched relative to this list of directories.  The resulting `.po'
     file will be written relative to the current directory, though.


   If INPUTFILE is `-', standard input is read.

Output file location
--------------------

`-o FILE'
`--output-file=FILE'
     Write output to specified file.


   The results are written to standard output if no output file is
specified or if it is `-'.

Message selection
-----------------

`-< NUMBER'
`--less-than=NUMBER'
     Print messages with less than NUMBER definitions, defaults to
     infinite if not set.

`-> NUMBER'
`--more-than=NUMBER'
     Print messages with more than NUMBER definitions, defaults to 1 if
     not set.

`-u'
`--unique'
     Shorthand for `--less-than=2'.  Requests that only unique messages
     be printed.


Input file syntax
-----------------

`-P'
`--properties-input'
     Assume the input files are Java ResourceBundles in Java
     `.properties' syntax, not in PO file syntax.

`--stringtable-input'
     Assume the input files are NeXTstep/GNUstep localized resource
     files in `.strings' syntax, not in PO file syntax.


Output details
--------------

`--force-po'
     Always write an output file even if it contains no message.

`-i'
`--indent'
     Write the .po file using indented style.

`--no-location'
     Do not write `#: FILENAME:LINE' lines.

`-n'
`--add-location'
     Generate `#: FILENAME:LINE' lines (default).

`--strict'
     Write out a strict Uniforum conforming PO file.  Note that this
     Uniforum format should be avoided because it doesn't support the
     GNU extensions.

`-p'
`--properties-output'
     Write out a Java ResourceBundle in Java `.properties' syntax.  Note
     that this file format doesn't support plural forms and silently
     drops obsolete messages.

`--stringtable-output'
     Write out a NeXTstep/GNUstep localized resource file in `.strings'
     syntax.  Note that this file format doesn't support plural forms.

`-w NUMBER'
`--width=NUMBER'
     Set the output page width.  Long strings in the output files will
     be split across multiple lines in order to ensure that each line's
     width (= number of screen columns) is less or equal to the given
     NUMBER.

`--no-wrap'
     Do not break long message lines.  Message lines whose width
     exceeds the output page width will not be split into several
     lines.  Only file reference lines which are wider than the output
     page width will be split.

`-s'
`--sort-output'
     Generate sorted output.  Note that using this option makes it much
     harder for the translator to understand each message's context.

`-F'
`--sort-by-file'
     Sort output by file location.

`--omit-header'
     Don't write header with `msgid ""' entry.


Informative output
------------------

`-h'
`--help'
     Display this help and exit.

`-V'
`--version'
     Output version information and exit.



File: gettext.info,  Node: msgcmp Invocation,  Next: msgattrib Invocation,  Prev: msgcomm Invocation,  Up: Manipulating

Invoking the `msgcmp' Program
=============================

     msgcmp [OPTION] DEF.po REF.pot

   The `msgcmp' program compares two Uniforum style .po files to check
that both contain the same set of msgid strings.  The DEF.po file is an
existing PO file with the translations.  The REF.pot file is the last
created PO file, or a PO Template file (generally created by
`xgettext').  This is useful for checking that you have translated each
and every message in your program.  Where an exact match cannot be
found, fuzzy matching is used to produce better diagnostics.

Input file location
-------------------

`DEF.po'
     Translations.

`REF.pot'
     References to the sources.

`-D DIRECTORY'
`--directory=DIRECTORY'
     Add DIRECTORY to the list of directories.  Source files are
     searched relative to this list of directories.


Operation modifiers
-------------------

`-m'
`--multi-domain'
     Apply REF.pot to each of the domains in DEF.po.


Input file syntax
-----------------

`-P'
`--properties-input'
     Assume the input files are Java ResourceBundles in Java
     `.properties' syntax, not in PO file syntax.

`--stringtable-input'
     Assume the input files are NeXTstep/GNUstep localized resource
     files in `.strings' syntax, not in PO file syntax.


Informative output
------------------

`-h'
`--help'
     Display this help and exit.

`-V'
`--version'
     Output version information and exit.



File: gettext.info,  Node: msgattrib Invocation,  Next: msgen Invocation,  Prev: msgcmp Invocation,  Up: Manipulating

Invoking the `msgattrib' Program
================================

     msgattrib [OPTION] [INPUTFILE]

   The `msgattrib' program filters the messages of a translation catalog
according to their attributes, and manipulates the attributes.

Input file location
-------------------

`INPUTFILE'
     Input PO file.

`-D DIRECTORY'
`--directory=DIRECTORY'
     Add DIRECTORY to the list of directories.  Source files are
     searched relative to this list of directories.  The resulting `.po'
     file will be written relative to the current directory, though.


   If no INPUTFILE is given or if it is `-', standard input is read.

Output file location
--------------------

`-o FILE'
`--output-file=FILE'
     Write output to specified file.


   The results are written to standard output if no output file is
specified or if it is `-'.

Message selection
-----------------

`--translated'
     Keep translated messages, remove untranslated messages.

`--untranslated'
     Keep untranslated messages, remove translated messages.

`--no-fuzzy'
     Remove `fuzzy' marked messages.

`--only-fuzzy'
     Keep `fuzzy' marked messages, remove all other messsages.

`--no-obsolete'
     Remove obsolete #~ messages.

`--only-obsolete'
     Keep obsolete #~ messages, remove all other messages.


Attribute manipulation
----------------------

Attributes are modified after the message selection/removal has been
performed.  If the `--only-file' or `--ignore-file' option is
specified, the attribute modification is applied only to those messages
that are listed in the ONLY-FILE and not listed in the IGNORE-FILE.

`--set-fuzzy'
     Set all messages `fuzzy'.

`--clear-fuzzy'
     Set all messages non-`fuzzy'.

`--set-obsolete'
     Set all messages obsolete.

`--clear-obsolete'
     Set all messages non-obsolete.

`--only-file=FILE'
     Limit the attribute changes to entries that are listed in FILE.
     FILE should be a PO or POT file.

`--ignore-file=FILE'
     Limit the attribute changes to entries that are not listed in FILE.
     FILE should be a PO or POT file.

`--fuzzy'
     Synonym for `--only-fuzzy --clear-fuzzy': It keeps only the fuzzy
     messages and removes their `fuzzy' mark.

`--obsolete'
     Synonym for `--only-obsolete --clear-obsolete': It keeps only the
     obsolete messages and makes them non-obsolete.


Input file syntax
-----------------

`-P'
`--properties-input'
     Assume the input file is a Java ResourceBundle in Java
     `.properties' syntax, not in PO file syntax.

`--stringtable-input'
     Assume the input file is a NeXTstep/GNUstep localized resource
     file in `.strings' syntax, not in PO file syntax.


Output details
--------------

`--force-po'
     Always write an output file even if it contains no message.

`-i'
`--indent'
     Write the .po file using indented style.

`--no-location'
     Do not write `#: FILENAME:LINE' lines.

`-n'
`--add-location'
     Generate `#: FILENAME:LINE' lines (default).

`--strict'
     Write out a strict Uniforum conforming PO file.  Note that this
     Uniforum format should be avoided because it doesn't support the
     GNU extensions.

`-p'
`--properties-output'
     Write out a Java ResourceBundle in Java `.properties' syntax.  Note
     that this file format doesn't support plural forms and silently
     drops obsolete messages.

`--stringtable-output'
     Write out a NeXTstep/GNUstep localized resource file in `.strings'
     syntax.  Note that this file format doesn't support plural forms.

`-w NUMBER'
`--width=NUMBER'
     Set the output page width.  Long strings in the output files will
     be split across multiple lines in order to ensure that each line's
     width (= number of screen columns) is less or equal to the given
     NUMBER.

`--no-wrap'
     Do not break long message lines.  Message lines whose width
     exceeds the output page width will not be split into several
     lines.  Only file reference lines which are wider than the output
     page width will be split.

`-s'
`--sort-output'
     Generate sorted output.  Note that using this option makes it much
     harder for the translator to understand each message's context.

`-F'
`--sort-by-file'
     Sort output by file location.


Informative output
------------------

`-h'
`--help'
     Display this help and exit.

`-V'
`--version'
     Output version information and exit.



File: gettext.info,  Node: msgen Invocation,  Next: msgexec Invocation,  Prev: msgattrib Invocation,  Up: Manipulating

Invoking the `msgen' Program
============================

     msgen [OPTION] INPUTFILE

   The `msgen' program creates an English translation catalog.  The
input file is the last created English PO file, or a PO Template file
(generally created by xgettext).  Untranslated entries are assigned a
translation that is identical to the msgid.

   Note: `msginit --no-translator --locale=en' performs a very similar
task.  The main difference is that `msginit' cares specially about the
header entry, whereas `msgen' doesn't.

Input file location
-------------------

`INPUTFILE'
     Input PO or POT file.

`-D DIRECTORY'
`--directory=DIRECTORY'
     Add DIRECTORY to the list of directories.  Source files are
     searched relative to this list of directories.  The resulting `.po'
     file will be written relative to the current directory, though.


   If INPUTFILE is `-', standard input is read.

Output file location
--------------------

`-o FILE'
`--output-file=FILE'
     Write output to specified file.


   The results are written to standard output if no output file is
specified or if it is `-'.

Input file syntax
-----------------

`-P'
`--properties-input'
     Assume the input file is a Java ResourceBundle in Java
     `.properties' syntax, not in PO file syntax.

`--stringtable-input'
     Assume the input file is a NeXTstep/GNUstep localized resource
     file in `.strings' syntax, not in PO file syntax.


Output details
--------------

`--force-po'
     Always write an output file even if it contains no message.

`-i'
`--indent'
     Write the .po file using indented style.

`--no-location'
     Do not write `#: FILENAME:LINE' lines.

`--add-location'
     Generate `#: FILENAME:LINE' lines (default).

`--strict'
     Write out a strict Uniforum conforming PO file.  Note that this
     Uniforum format should be avoided because it doesn't support the
     GNU extensions.

`-p'
`--properties-output'
     Write out a Java ResourceBundle in Java `.properties' syntax.  Note
     that this file format doesn't support plural forms and silently
     drops obsolete messages.

`--stringtable-output'
     Write out a NeXTstep/GNUstep localized resource file in `.strings'
     syntax.  Note that this file format doesn't support plural forms.

`-w NUMBER'
`--width=NUMBER'
     Set the output page width.  Long strings in the output files will
     be split across multiple lines in order to ensure that each line's
     width (= number of screen columns) is less or equal to the given
     NUMBER.

`--no-wrap'
     Do not break long message lines.  Message lines whose width
     exceeds the output page width will not be split into several
     lines.  Only file reference lines which are wider than the output
     page width will be split.

`-s'
`--sort-output'
     Generate sorted output.  Note that using this option makes it much
     harder for the translator to understand each message's context.

`-F'
`--sort-by-file'
     Sort output by file location.


Informative output
------------------

`-h'
`--help'
     Display this help and exit.

`-V'
`--version'
     Output version information and exit.



File: gettext.info,  Node: msgexec Invocation,  Next: libgettextpo,  Prev: msgen Invocation,  Up: Manipulating

Invoking the `msgexec' Program
==============================

     msgexec [OPTION] COMMAND [COMMAND-OPTION]

   The `msgexec' program applies a command to all translations of a
translation catalog.  The COMMAND can be any program that reads a
translation from standard input.  It is invoked once for each
translation.  Its output becomes msgexec's output.  `msgexec''s return
code is the maximum return code across all invocations.

   A special builtin command called `0' outputs the translation,
followed by a null byte.  The output of `msgexec 0' is suitable as
input for `xargs -0'.

   During each COMMAND invocation, the environment variable
`MSGEXEC_MSGID' is bound to the message's msgid, and the environment
variable `MSGEXEC_LOCATION' is bound to the location in the PO file of
the message.

   Note: It is your responsibility to ensure that the COMMAND can cope
with input encoded in the translation catalog's encoding.  If the
COMMAND wants input in a particular encoding, you can in a first step
convert the translation catalog to that encoding using the `msgconv'
program, before invoking `msgexec'.  If the COMMAND wants input in the
locale's encoding, but you want to avoid the locale's encoding, then
you can first convert the translation catalog to UTF-8 using the
`msgconv' program and then make `msgexec' work in an UTF-8 locale, by
using the `LC_ALL' environment variable.

Input file location
-------------------

`-i INPUTFILE'
`--input=INPUTFILE'
     Input PO file.

`-D DIRECTORY'
`--directory=DIRECTORY'
     Add DIRECTORY to the list of directories.  Source files are
     searched relative to this list of directories.  The resulting `.po'
     file will be written relative to the current directory, though.


   If no INPUTFILE is given or if it is `-', standard input is read.

Input file syntax
-----------------

`-P'
`--properties-input'
     Assume the input file is a Java ResourceBundle in Java
     `.properties' syntax, not in PO file syntax.

`--stringtable-input'
     Assume the input file is a NeXTstep/GNUstep localized resource
     file in `.strings' syntax, not in PO file syntax.


Informative output
------------------

`-h'
`--help'
     Display this help and exit.

`-V'
`--version'
     Output version information and exit.



File: gettext.info,  Node: libgettextpo,  Prev: msgexec Invocation,  Up: Manipulating

Writing your own programs that process PO files
===============================================

For the tasks for which a combination of `msgattrib', `msgcat' etc.  is
not sufficient, a set of C functions is provided in a library, to make
it possible to process PO files in your own programs.  When you use
this library, you don't need to write routines to parse the PO file;
instead, you retreive a pointer in memory to each of messages contained
in the PO file.  Functions for writing PO files are not provided at
this time.

   The functions are declared in the header file `<gettext-po.h>', and
are defined in a library called `libgettextpo'.

 - Data Type: po_file_t
     This is a pointer type that refers to the contents of a PO file,
     after it has been read into memory.

 - Data Type: po_message_iterator_t
     This is a pointer type that refers to an iterator that produces a
     sequence of messages.

 - Data Type: po_message_t
     This is a pointer type that refers to a message of a PO file,
     including its translation.

 - Function: po_file_t po_file_read (const char *FILENAME)
     The `po_file_read' function reads a PO file into memory.  The file
     name is given as argument.  The return value is a handle to the PO
     file's contents, valid until `po_file_free' is called on it.  In
     case of error, the return value is `NULL', and `errno' is set.

 - Function: void po_file_free (po_file_t FILE)
     The `po_file_free' function frees a PO file's contents from memory,
     including all messages that are only implicitly accessible through
     iterators.

 - Function: const char * const * po_file_domains (po_file_t FILE)
     The `po_file_domains' function returns the domains for which the
     given PO file has messages.  The return value is a `NULL'
     terminated array which is valid as long as the FILE handle is
     valid.  For PO files which contain no `domain' directive, the
     return value contains only one domain, namely the default domain
     `"messages"'.

 - Function: po_message_iterator_t po_message_iterator (po_file_t FILE,
          const char *DOMAIN)
     The `po_message_iterator' returns an iterator that will produce the
     messages of FILE that belong to the given DOMAIN.  If DOMAIN is
     `NULL', the default domain is used instead.  To list the messages,
     use the function `po_next_message' repeatedly.

 - Function: void po_message_iterator_free (po_message_iterator_t
          ITERATOR)
     The `po_message_iterator_free' function frees an iterator
     previously allocated through the `po_message_iterator' function.

 - Function: po_message_t po_next_message (po_message_iterator_t
          ITERATOR)
     The `po_next_message' function returns the next message from
     ITERATOR and advances the iterator.  It returns `NULL' when the
     iterator has reached the end of its message list.

   The following functions returns details of a `po_message_t'.  Recall
that the results are valid as long as the FILE handle is valid.

 - Function: const char * po_message_msgid (po_message_t MESSAGE)
     The `po_message_msgid' function returns the `msgid' (untranslated
     English string) of a message.  This is guaranteed to be non-`NULL'.

 - Function: const char * po_message_msgid_plural (po_message_t MESSAGE)
     The `po_message_msgid_plural' function returns the `msgid_plural'
     (untranslated English plural string) of a message with plurals, or
     `NULL' for a message without plural.

 - Function: const char * po_message_msgstr (po_message_t MESSAGE)
     The `po_message_msgstr' function returns the `msgstr' (translation)
     of a message.  For an untranslated message, the return value is an
     empty string.

 - Function: const char * po_message_msgstr_plural (po_message_t
          MESSAGE, int INDEX)
     The `po_message_msgstr_plural' function returns the
     `msgstr[INDEX]' of a message with plurals, or `NULL' when the
     INDEX is out of range or for a message without plural.

   Here is an example code how these functions can be used.

     const char *filename = ...;
     po_file_t file = po_file_read (filename);
     
     if (file == NULL)
       error (EXIT_FAILURE, errno, "couldn't open the PO file %s", filename);
     {
       const char * const *domains = po_file_domains (file);
       const char * const *domainp;
     
       for (domainp = domains; *domainp; domainp++)
         {
           const char *domain = *domainp;
           po_message_iterator_t iterator = po_message_iterator (file, domain);
     
           for (;;)
             {
               po_message_t *message = po_next_message (iterator);
     
               if (message == NULL)
                 break;
               {
                 const char *msgid = po_message_msgid (message);
                 const char *msgstr = po_message_msgstr (message);
     
                 ...
               }
             }
           po_message_iterator_free (iterator);
         }
     }
     po_file_free (file);


File: gettext.info,  Node: Binaries,  Next: Users,  Prev: Manipulating,  Up: Top

Producing Binary MO Files
*************************

* Menu:

* msgfmt Invocation::           Invoking the `msgfmt' Program
* msgunfmt Invocation::         Invoking the `msgunfmt' Program
* MO Files::                    The Format of GNU MO Files


File: gettext.info,  Node: msgfmt Invocation,  Next: msgunfmt Invocation,  Prev: Binaries,  Up: Binaries

Invoking the `msgfmt' Program
=============================

     msgfmt [OPTION] FILENAME.po ...

   The `msgfmt' programs generates a binary message catalog from a
textual translation description.

Input file location
-------------------

`FILENAME.po ...'

`-D DIRECTORY'
`--directory=DIRECTORY'
     Add DIRECTORY to the list of directories.  Source files are
     searched relative to this list of directories.  The resulting `.po'
     file will be written relative to the current directory, though.


   If an input file is `-', standard input is read.

Operation mode
--------------

`-j'
`--java'
     Java mode: generate a Java `ResourceBundle' class.

`--java2'
     Like -java, and assume Java2 (JDK 1.2 or higher).

`--tcl'
     Tcl mode: generate a tcl/msgcat `.msg' file.

`--qt'
     Qt mode: generate a Qt `.qm' file.


Output file location
--------------------

`-o FILE'
`--output-file=FILE'
     Write output to specified file.

`--strict'
     Direct the program to work strictly following the Uniforum/Sun
     implementation.  Currently this only affects the naming of the
     output file.  If this option is not given the name of the output
     file is the same as the domain name.  If the strict Uniforum mode
     is enabled the suffix `.mo' is added to the file name if it is not
     already present.

     We find this behaviour of Sun's implementation rather silly and so
     by default this mode is _not_ selected.


   If the output FILE is `-', output is written to standard output.

Output file location in Java mode
---------------------------------

`-r RESOURCE'
`--resource=RESOURCE'
     Specify the resource name.

`-l LOCALE'
`--locale=LOCALE'
     Specify the locale name, either a language specification of the
     form LL or a combined language and country specification of the
     form LL_CC.

`-d DIRECTORY'
     Specify the base directory of classes directory hierarchy.


   The class name is determined by appending the locale name to the
resource name, separated with an underscore.  The `-d' option is
mandatory.  The class is written under the specified directory.

Output file location in Tcl mode
--------------------------------

`-l LOCALE'
`--locale=LOCALE'
     Specify the locale name, either a language specification of the
     form LL or a combined language and country specification of the
     form LL_CC.

`-d DIRECTORY'
     Specify the base directory of `.msg' message catalogs.


   The `-l' and `-d' options are mandatory.  The `.msg' file is written
in the specified directory.

Input file syntax
-----------------

`-P'
`--properties-input'
     Assume the input files are Java ResourceBundles in Java
     `.properties' syntax, not in PO file syntax.

`--stringtable-input'
     Assume the input files are NeXTstep/GNUstep localized resource
     files in `.strings' syntax, not in PO file syntax.


Input file interpretation
-------------------------

`-c'
`--check'
     Perform all the checks implied by `--check-format',
     `--check-header', `--check-domain'.

`--check-format'
     Check language dependent format strings.

     If the string represents a format string used in a `printf'-like
     function both strings should have the same number of `%' format
     specifiers, with matching types.  If the flag `c-format' or
     `possible-c-format' appears in the special comment <#,> for this
     entry a check is performed.  For example, the check will diagnose
     using `%.*s' against `%s', or `%d' against `%s', or `%d' against
     `%x'.  It can even handle positional parameters.

     Normally the `xgettext' program automatically decides whether a
     string is a format string or not.  This algorithm is not perfect,
     though.  It might regard a string as a format string though it is
     not used in a `printf'-like function and so `msgfmt' might report
     errors where there are none.

     To solve this problem the programmer can dictate the decision to
     the `xgettext' program (*note c-format::).  The translator should
     not consider removing the flag from the <#,> line.  This "fix"
     would be reversed again as soon as `msgmerge' is called the next
     time.

`--check-header'
     Verify presence and contents of the header entry.  *Note Header
     Entry::, for a description of the various fields in the header
     entry.

`--check-domain'
     Check for conflicts between domain directives and the
     `--output-file' option

`-C'
`--check-compatibility'
     Check that GNU msgfmt behaves like X/Open msgfmt.  This will give
     an error when attempting to use the GNU extensions.

`--check-accelerators[=CHAR]'
     Check presence of keyboard accelerators for menu items.  This is
     based on the convention used in some GUIs that a keyboard
     accelerator in a menu item string is designated by an immediately
     preceding `&' character.  Sometimes a keyboard accelerator is also
     called "keyboard mnemonic".  This check verifies that if the
     untranslated string has exactly one `&' character, the translated
     string has exactly one `&' as well.  If this option is given with
     a CHAR argument, this CHAR should be a non-alphanumeric character
     and is used as keyboard acceleator mark instead of `&'.

`-f'
`--use-fuzzy'
     Use fuzzy entries in output.  Note that using this option is
     usually wrong, because fuzzy messages are exactly those which have
     not been validated by a human translator.


Output details
--------------

`-a NUMBER'
`--alignment=NUMBER'
     Align strings to NUMBER bytes (default: 1).

`--no-hash'
     Don't include a hash table in the binary file.  Lookup will be
     more expensive at run time (binary search instead of hash table
     lookup).


Informative output
------------------

`-h'
`--help'
     Display this help and exit.

`-V'
`--version'
     Output version information and exit.

`--statistics'
     Print statistics about translations.

`-v'
`--verbose'
     Increase verbosity level.



File: gettext.info,  Node: msgunfmt Invocation,  Next: MO Files,  Prev: msgfmt Invocation,  Up: Binaries

Invoking the `msgunfmt' Program
===============================

     msgunfmt [OPTION] [FILE]...

   The `msgunfmt' program converts a binary message catalog to a
Uniforum style .po file.

Operation mode
--------------

`-j'
`--java'
     Java mode: input is a Java `ResourceBundle' class.

`--tcl'
     Tcl mode: input is a tcl/msgcat `.msg' file.


Input file location
-------------------

`FILE ...'
     Input .mo files.


   If no input FILE is given or if it is `-', standard input is read.

Input file location in Java mode
--------------------------------

`-r RESOURCE'
`--resource=RESOURCE'
     Specify the resource name.

`-l LOCALE'
`--locale=LOCALE'
     Specify the locale name, either a language specification of the
     form LL or a combined language and country specification of the
     form LL_CC.


   The class name is determined by appending the locale name to the
resource name, separated with an underscore.  The class is located
using the `CLASSPATH'.

Input file location in Tcl mode
-------------------------------

`-l LOCALE'
`--locale=LOCALE'
     Specify the locale name, either a language specification of the
     form LL or a combined language and country specification of the
     form LL_CC.

`-d DIRECTORY'
     Specify the base directory of `.msg' message catalogs.


   The `-l' and `-d' options are mandatory.  The `.msg' file is located
in the specified directory.

Output file location
--------------------

`-o FILE'
`--output-file=FILE'
     Write output to specified file.


   The results are written to standard output if no output file is
specified or if it is `-'.

Output details
--------------

`--force-po'
     Always write an output file even if it contains no message.

`-i'
`--indent'
     Write the .po file using indented style.

`--strict'
     Write out a strict Uniforum conforming PO file.  Note that this
     Uniforum format should be avoided because it doesn't support the
     GNU extensions.

`-p'
`--properties-output'
     Write out a Java ResourceBundle in Java `.properties' syntax.  Note
     that this file format doesn't support plural forms and silently
     drops obsolete messages.

`--stringtable-output'
     Write out a NeXTstep/GNUstep localized resource file in `.strings'
     syntax.  Note that this file format doesn't support plural forms.

`-w NUMBER'
`--width=NUMBER'
     Set the output page width.  Long strings in the output files will
     be split across multiple lines in order to ensure that each line's
     width (= number of screen columns) is less or equal to the given
     NUMBER.

`--no-wrap'
     Do not break long message lines.  Message lines whose width
     exceeds the output page width will not be split into several
     lines.  Only file reference lines which are wider than the output
     page width will be split.

`-s'
`--sort-output'
     Generate sorted output.  Note that using this option makes it much
     harder for the translator to understand each message's context.


Informative output
------------------

`-h'
`--help'
     Display this help and exit.

`-V'
`--version'
     Output version information and exit.

`-v'
`--verbose'
     Increase verbosity level.



File: gettext.info,  Node: MO Files,  Prev: msgunfmt Invocation,  Up: Binaries

The Format of GNU MO Files
==========================

The format of the generated MO files is best described by a picture,
which appears below.

   The first two words serve the identification of the file.  The magic
number will always signal GNU MO files.  The number is stored in the
byte order of the generating machine, so the magic number really is two
numbers: `0x950412de' and `0xde120495'.  The second word describes the
current revision of the file format.  For now the revision is 0.  This
might change in future versions, and ensures that the readers of MO
files can distinguish new formats from old ones, so that both can be
handled correctly.  The version is kept separate from the magic number,
instead of using different magic numbers for different formats, mainly
because `/etc/magic' is not updated often.  It might be better to have
magic separated from internal format version identification.

   Follow a number of pointers to later tables in the file, allowing
for the extension of the prefix part of MO files without having to
recompile programs reading them.  This might become useful for later
inserting a few flag bits, indication about the charset used, new
tables, or other things.

   Then, at offset O and offset T in the picture, two tables of string
descriptors can be found.  In both tables, each string descriptor uses
two 32 bits integers, one for the string length, another for the offset
of the string in the MO file, counting in bytes from the start of the
file.  The first table contains descriptors for the original strings,
and is sorted so the original strings are in increasing lexicographical
order.  The second table contains descriptors for the translated
strings, and is parallel to the first table: to find the corresponding
translation one has to access the array slot in the second array with
the same index.

   Having the original strings sorted enables the use of simple binary
search, for when the MO file does not contain an hashing table, or for
when it is not practical to use the hashing table provided in the MO
file.  This also has another advantage, as the empty string in a PO
file GNU `gettext' is usually _translated_ into some system information
attached to that particular MO file, and the empty string necessarily
becomes the first in both the original and translated tables, making
the system information very easy to find.

   The size S of the hash table can be zero.  In this case, the hash
table itself is not contained in the MO file.  Some people might prefer
this because a precomputed hashing table takes disk space, and does not
win _that_ much speed.  The hash table contains indices to the sorted
array of strings in the MO file.  Conflict resolution is done by double
hashing.  The precise hashing algorithm used is fairly dependent on GNU
`gettext' code, and is not documented here.

   As for the strings themselves, they follow the hash file, and each
is terminated with a <NUL>, and this <NUL> is not counted in the length
which appears in the string descriptor.  The `msgfmt' program has an
option selecting the alignment for MO file strings.  With this option,
each string is separately aligned so it starts at an offset which is a
multiple of the alignment value.  On some RISC machines, a correct
alignment will speed things up.

   Plural forms are stored by letting the plural of the original string
follow the singular of the original string, separated through a <NUL>
byte.  The length which appears in the string descriptor includes both.
However, only the singular of the original string takes part in the
hash table lookup.  The plural variants of the translation are all
stored consecutively, separated through a <NUL> byte.  Here also, the
length in the string descriptor includes all of them.

   Nothing prevents a MO file from having embedded <NUL>s in strings.
However, the program interface currently used already presumes that
strings are <NUL> terminated, so embedded <NUL>s are somewhat useless.
But the MO file format is general enough so other interfaces would be
later possible, if for example, we ever want to implement wide
characters right in MO files, where <NUL> bytes may accidently appear.
(No, we don't want to have wide characters in MO files.  They would
make the file unnecessarily large, and the `wchar_t' type being
platform dependent, MO files would be platform dependent as well.)

   This particular issue has been strongly debated in the GNU `gettext'
development forum, and it is expectable that MO file format will evolve
or change over time.  It is even possible that many formats may later
be supported concurrently.  But surely, we have to start somewhere, and
the MO file format described here is a good start.  Nothing is cast in
concrete, and the format may later evolve fairly easily, so we should
feel comfortable with the current approach.

             byte
                  +------------------------------------------+
               0  | magic number = 0x950412de                |
                  |                                          |
               4  | file format revision = 0                 |
                  |                                          |
               8  | number of strings                        |  == N
                  |                                          |
              12  | offset of table with original strings    |  == O
                  |                                          |
              16  | offset of table with translation strings |  == T
                  |                                          |
              20  | size of hashing table                    |  == S
                  |                                          |
              24  | offset of hashing table                  |  == H
                  |                                          |
                  .                                          .
                  .    (possibly more entries later)         .
                  .                                          .
                  |                                          |
               O  | length & offset 0th string  ----------------.
           O + 8  | length & offset 1st string  ------------------.
                   ...                                    ...   | |
     O + ((N-1)*8)| length & offset (N-1)th string           |  | |
                  |                                          |  | |
               T  | length & offset 0th translation  ---------------.
           T + 8  | length & offset 1st translation  -----------------.
                   ...                                    ...   | | | |
     T + ((N-1)*8)| length & offset (N-1)th translation      |  | | | |
                  |                                          |  | | | |
               H  | start hash table                         |  | | | |
                   ...                                    ...   | | | |
       H + S * 4  | end hash table                           |  | | | |
                  |                                          |  | | | |
                  | NUL terminated 0th string  <----------------' | | |
                  |                                          |    | | |
                  | NUL terminated 1st string  <------------------' | |
                  |                                          |      | |
                   ...                                    ...       | |
                  |                                          |      | |
                  | NUL terminated 0th translation  <---------------' |
                  |                                          |        |
                  | NUL terminated 1st translation  <-----------------'
                  |                                          |
                   ...                                    ...
                  |                                          |
                  +------------------------------------------+


File: gettext.info,  Node: Users,  Next: Programmers,  Prev: Binaries,  Up: Top

The User's View
***************

When GNU `gettext' will truly have reached its goal, average users
should feel some kind of astonished pleasure, seeing the effect of that
strange kind of magic that just makes their own native language appear
everywhere on their screens.  As for naive users, they would ideally
have no special pleasure about it, merely taking their own language for
_granted_, and becoming rather unhappy otherwise.

   So, let's try to describe here how we would like the magic to
operate, as we want the users' view to be the simplest, among all ways
one could look at GNU `gettext'.  All other software engineers:
programmers, translators, maintainers, should work together in such a
way that the magic becomes possible.  This is a long and progressive
undertaking, and information is available about the progress of the
Translation Project.

   When a package is distributed, there are two kinds of users:
"installers" who fetch the distribution, unpack it, configure it,
compile it and install it for themselves or others to use; and "end
users" that call programs of the package, once these have been
installed at their site.  GNU `gettext' is offering magic for both
installers and end users.

* Menu:

* Matrix::                      The Current `ABOUT-NLS' Matrix
* Installers::                  Magic for Installers
* End Users::                   Magic for End Users


File: gettext.info,  Node: Matrix,  Next: Installers,  Prev: Users,  Up: Users

The Current `ABOUT-NLS' Matrix
==============================

Languages are not equally supported in all packages using GNU
`gettext'.  To know if some package uses GNU `gettext', one may check
the distribution for the `ABOUT-NLS' information file, for some `LL.po'
files, often kept together into some `po/' directory, or for an `intl/'
directory.  Internationalized packages have usually many `LL.po' files,
where LL represents the language.  *Note End Users:: for a complete
description of the format for LL.

   More generally, a matrix is available for showing the current state
of the Translation Project, listing which packages are prepared for
multi-lingual messages, and which languages are supported by each.
Because this information changes often, this matrix is not kept within
this GNU `gettext' manual.  This information is often found in file
`ABOUT-NLS' from various distributions, but is also as old as the
distribution itself.  A recent copy of this `ABOUT-NLS' file,
containing up-to-date information, should generally be found on the
Translation Project sites, and also on most GNU archive sites.


File: gettext.info,  Node: Installers,  Next: End Users,  Prev: Matrix,  Up: Users

Magic for Installers
====================

By default, packages fully using GNU `gettext', internally, are
installed in such a way that they to allow translation of messages.  At
_configuration_ time, those packages should automatically detect
whether the underlying host system already provides the GNU `gettext'
functions.  If not, the GNU `gettext' library should be automatically
prepared and used.  Installers may use special options at configuration
time for changing this behavior.  The command `./configure
--with-included-gettext' bypasses system `gettext' to use the included
GNU `gettext' instead, while `./configure --disable-nls' produces
programs totally unable to translate messages.

   Internationalized packages have usually many `LL.po' files.  Unless
translations are disabled, all those available are installed together
with the package.  However, the environment variable `LINGUAS' may be
set, prior to configuration, to limit the installed set.  `LINGUAS'
should then contain a space separated list of two-letter codes, stating
which languages are allowed.


File: gettext.info,  Node: End Users,  Prev: Installers,  Up: Users

Magic for End Users
===================

We consider here those packages using GNU `gettext' internally, and for
which the installers did not disable translation at _configure_ time.
Then, users only have to set the `LANG' environment variable to the
appropriate `LL_CC' combination prior to using the programs in the
package.  *Note Matrix::.  For example, let's presume a German site.
At the shell prompt, users merely have to execute `setenv LANG de_DE'
(in `csh') or `export LANG; LANG=de_DE' (in `sh').  They could even do
this from their `.login' or `.profile' file.


File: gettext.info,  Node: Programmers,  Next: Translators,  Prev: Users,  Up: Top

The Programmer's View
*********************

One aim of the current message catalog implementation provided by GNU
`gettext' was to use the system's message catalog handling, if the
installer wishes to do so.  So we perhaps should first take a look at
the solutions we know about.  The people in the POSIX committee did not
manage to agree on one of the semi-official standards which we'll
describe below.  In fact they couldn't agree on anything, so they
decided only to include an example of an interface.  The major Unix
vendors are split in the usage of the two most important
specifications: X/Open's catgets vs. Uniforum's gettext interface.
We'll describe them both and later explain our solution of this dilemma.

* Menu:

* catgets::                     About `catgets'
* gettext::                     About `gettext'
* Comparison::                  Comparing the two interfaces
* Using libintl.a::             Using libintl.a in own programs
* gettext grok::                Being a `gettext' grok
* Temp Programmers::            Temporary Notes for the Programmers Chapter


File: gettext.info,  Node: catgets,  Next: gettext,  Prev: Programmers,  Up: Programmers

About `catgets'
===============

The `catgets' implementation is defined in the X/Open Portability
Guide, Volume 3, XSI Supplementary Definitions, Chapter 5.  But the
process of creating this standard seemed to be too slow for some of the
Unix vendors so they created their implementations on preliminary
versions of the standard.  Of course this leads again to problems while
writing platform independent programs: even the usage of `catgets' does
not guarantee a unique interface.

   Another, personal comment on this that only a bunch of committee
members could have made this interface.  They never really tried to
program using this interface.  It is a fast, memory-saving
implementation, an user can happily live with it.  But programmers hate
it (at least I and some others do...)

   But we must not forget one point: after all the trouble with
transfering the rights on Unix(tm) they at last came to X/Open, the
very same who published this specification.  This leads me to making
the prediction that this interface will be in future Unix standards
(e.g. Spec1170) and therefore part of all Unix implementation
(implementations, which are _allowed_ to wear this name).

* Menu:

* Interface to catgets::        The interface
* Problems with catgets::       Problems with the `catgets' interface?!


File: gettext.info,  Node: Interface to catgets,  Next: Problems with catgets,  Prev: catgets,  Up: catgets

The Interface
-------------

The interface to the `catgets' implementation consists of three
functions which correspond to those used in file access: `catopen' to
open the catalog for using, `catgets' for accessing the message tables,
and `catclose' for closing after work is done.  Prototypes for the
functions and the needed definitions are in the `<nl_types.h>' header
file.

   `catopen' is used like in this:

     nl_catd catd = catopen ("catalog_name", 0);

   The function takes as the argument the name of the catalog.  This
usual refers to the name of the program or the package.  The second
parameter is not further specified in the standard.  I don't even know
whether it is implemented consistently among various systems.  So the
common advice is to use `0' as the value.  The return value is a handle
to the message catalog, equivalent to handles to file returned by
`open'.

   This handle is of course used in the `catgets' function which can be
used like this:

     char *translation = catgets (catd, set_no, msg_id, "original string");

   The first parameter is this catalog descriptor.  The second parameter
specifies the set of messages in this catalog, in which the message
described by `msg_id' is obtained.  `catgets' therefore uses a
three-stage addressing:

     catalog name => set number => message ID => translation

   The fourth argument is not used to address the translation.  It is
given as a default value in case when one of the addressing stages
fail.  One important thing to remember is that although the return type
of catgets is `char *' the resulting string _must not_ be changed.  It
should better be `const char *', but the standard is published in 1988,
one year before ANSI C.

The last of these functions is used and behaves as expected:

     catclose (catd);

   After this no `catgets' call using the descriptor is legal anymore.


File: gettext.info,  Node: Problems with catgets,  Prev: Interface to catgets,  Up: catgets

Problems with the `catgets' Interface?!
---------------------------------------

Now that this description seemed to be really easy -- where are the
problems we speak of?  In fact the interface could be used in a
reasonable way, but constructing the message catalogs is a pain.  The
reason for this lies in the third argument of `catgets': the unique
message ID.  This has to be a numeric value for all messages in a single
set.  Perhaps you could imagine the problems keeping such a list while
changing the source code.  Add a new message here, remove one there.  Of
course there have been developed a lot of tools helping to organize this
chaos but one as the other fails in one aspect or the other.  We don't
want to say that the other approach has no problems but they are far
more easy to manage.


File: gettext.info,  Node: gettext,  Next: Comparison,  Prev: catgets,  Up: Programmers

About `gettext'
===============

The definition of the `gettext' interface comes from a Uniforum
proposal.  It was submitted there by Sun, who had implemented the
`gettext' function in SunOS 4, around 1990.  Nowadays, the `gettext'
interface is specified by the OpenI18N standard.

   The main point about this solution is that it does not follow the
method of normal file handling (open-use-close) and that it does not
burden the programmer with so many tasks, especially the unique key
handling.  Of course here also a unique key is needed, but this key is
the message itself (how long or short it is).  See *Note Comparison::
for a more detailed comparison of the two methods.

   The following section contains a rather detailed description of the
interface.  We make it that detailed because this is the interface we
chose for the GNU `gettext' Library.  Programmers interested in using
this library will be interested in this description.

* Menu:

* Interface to gettext::        The interface
* Ambiguities::                 Solving ambiguities
* Locating Catalogs::           Locating message catalog files
* Charset conversion::          How to request conversion to Unicode
* Plural forms::                Additional functions for handling plurals
* GUI program problems::        Another technique for solving ambiguities
* Optimized gettext::           Optimization of the *gettext functions


File: gettext.info,  Node: Interface to gettext,  Next: Ambiguities,  Prev: gettext,  Up: gettext

The Interface
-------------

The minimal functionality an interface must have is a) to select a
domain the strings are coming from (a single domain for all programs is
not reasonable because its construction and maintenance is difficult,
perhaps impossible) and b) to access a string in a selected domain.

   This is principally the description of the `gettext' interface.  It
has a global domain which unqualified usages reference.  Of course this
domain is selectable by the user.

     char *textdomain (const char *domain_name);

   This provides the possibility to change or query the current status
of the current global domain of the `LC_MESSAGE' category.  The
argument is a null-terminated string, whose characters must be legal in
the use in filenames.  If the DOMAIN_NAME argument is `NULL', the
function returns the current value.  If no value has been set before,
the name of the default domain is returned: _messages_.  Please note
that although the return value of `textdomain' is of type `char *' no
changing is allowed.  It is also important to know that no checks of
the availability are made.  If the name is not available you will see
this by the fact that no translations are provided.

To use a domain set by `textdomain' the function

     char *gettext (const char *msgid);

is to be used.  This is the simplest reasonable form one can imagine.
The translation of the string MSGID is returned if it is available in
the current domain.  If it is not available, the argument itself is
returned.  If the argument is `NULL' the result is undefined.

   One thing which should come into mind is that no explicit dependency
to the used domain is given.  The current value of the domain for the
`LC_MESSAGES' locale is used.  If this changes between two executions
of the same `gettext' call in the program, both calls reference a
different message catalog.

   For the easiest case, which is normally used in internationalized
packages, once at the beginning of execution a call to `textdomain' is
issued, setting the domain to a unique name, normally the package name.
In the following code all strings which have to be translated are
filtered through the gettext function.  That's all, the package speaks
your language.


File: gettext.info,  Node: Ambiguities,  Next: Locating Catalogs,  Prev: Interface to gettext,  Up: gettext

Solving Ambiguities
-------------------

While this single name domain works well for most applications there
might be the need to get translations from more than one domain.  Of
course one could switch between different domains with calls to
`textdomain', but this is really not convenient nor is it fast.  A
possible situation could be one case subject to discussion during this
writing:  all error messages of functions in the set of common used
functions should go into a separate domain `error'.  By this mean we
would only need to translate them once.  Another case are messages from
a library, as these _have_ to be independent of the current domain set
by the application.

For this reasons there are two more functions to retrieve strings:

     char *dgettext (const char *domain_name, const char *msgid);
     char *dcgettext (const char *domain_name, const char *msgid,
                      int category);

   Both take an additional argument at the first place, which
corresponds to the argument of `textdomain'.  The third argument of
`dcgettext' allows to use another locale but `LC_MESSAGES'.  But I
really don't know where this can be useful.  If the DOMAIN_NAME is
`NULL' or CATEGORY has an value beside the known ones, the result is
undefined.  It should also be noted that this function is not part of
the second known implementation of this function family, the one found
in Solaris.

   A second ambiguity can arise by the fact, that perhaps more than one
domain has the same name.  This can be solved by specifying where the
needed message catalog files can be found.

     char *bindtextdomain (const char *domain_name,
                           const char *dir_name);

   Calling this function binds the given domain to a file in the
specified directory (how this file is determined follows below).
Especially a file in the systems default place is not favored against
the specified file anymore (as it would be by solely using
`textdomain').  A `NULL' pointer for the DIR_NAME parameter returns the
binding associated with DOMAIN_NAME.  If DOMAIN_NAME itself is `NULL'
nothing happens and a `NULL' pointer is returned.  Here again as for
all the other functions is true that none of the return value must be
changed!

   It is important to remember that relative path names for the
DIR_NAME parameter can be trouble.  Since the path is always computed
relative to the current directory different results will be achieved
when the program executes a `chdir' command.  Relative paths should
always be avoided to avoid dependencies and unreliabilities.


File: gettext.info,  Node: Locating Catalogs,  Next: Charset conversion,  Prev: Ambiguities,  Up: gettext

Locating Message Catalog Files
------------------------------

Because many different languages for many different packages have to be
stored we need some way to add these information to file message catalog
files.  The way usually used in Unix environments is have this encoding
in the file name.  This is also done here.  The directory name given in
`bindtextdomain's second argument (or the default directory), followed
by the value and name of the locale and the domain name are
concatenated:

     DIR_NAME/LOCALE/LC_CATEGORY/DOMAIN_NAME.mo

   The default value for DIR_NAME is system specific.  For the GNU
library, and for packages adhering to its conventions, it's:
     /usr/local/share/locale

LOCALE is the value of the locale whose name is this `LC_CATEGORY'.
For `gettext' and `dgettext' this `LC_CATEGORY' is always
`LC_MESSAGES'.(1) The value of the locale is determined through
`setlocale (LC_CATEGORY, NULL)'.  (2) `dcgettext' specifies the locale
category by the third argument.

   ---------- Footnotes ----------

   (1) Some system, eg Ultrix, don't have `LC_MESSAGES'.  Here we use a
more or less arbitrary value for it, namely 1729, the smallest positive
integer which can be represented in two different ways as the sum of
two cubes.

   (2) When the system does not support `setlocale' its behavior in
setting the locale values is simulated by looking at the environment
variables.


File: gettext.info,  Node: Charset conversion,  Next: Plural forms,  Prev: Locating Catalogs,  Up: gettext

How to specify the output character set `gettext' uses
------------------------------------------------------

`gettext' not only looks up a translation in a message catalog.  It
also converts the translation on the fly to the desired output character
set.  This is useful if the user is working in a different character set
than the translator who created the message catalog, because it avoids
distributing variants of message catalogs which differ only in the
character set.

   The output character set is, by default, the value of `nl_langinfo
(CODESET)', which depends on the `LC_CTYPE' part of the current locale.
But programs which store strings in a locale independent way (e.g.
UTF-8) can request that `gettext' and related functions return the
translations in that encoding, by use of the `bind_textdomain_codeset'
function.

   Note that the MSGID argument to `gettext' is not subject to
character set conversion.  Also, when `gettext' does not find a
translation for MSGID, it returns MSGID unchanged - independently of
the current output character set.  It is therefore recommended that all
MSGIDs be US-ASCII strings.

 - Function: char * bind_textdomain_codeset (const char *DOMAINNAME,
          const char *CODESET)
     The `bind_textdomain_codeset' function can be used to specify the
     output character set for message catalogs for domain DOMAINNAME.
     The CODESET argument must be a valid codeset name which can be used
     for the `iconv_open' function, or a null pointer.

     If the CODESET parameter is the null pointer,
     `bind_textdomain_codeset' returns the currently selected codeset
     for the domain with the name DOMAINNAME.  It returns `NULL' if no
     codeset has yet been selected.

     The `bind_textdomain_codeset' function can be used several times.
     If used multiple times with the same DOMAINNAME argument, the
     later call overrides the settings made by the earlier one.

     The `bind_textdomain_codeset' function returns a pointer to a
     string containing the name of the selected codeset.  The string is
     allocated internally in the function and must not be changed by the
     user.  If the system went out of core during the execution of
     `bind_textdomain_codeset', the return value is `NULL' and the
     global variable ERRNO is set accordingly.


File: gettext.info,  Node: Plural forms,  Next: GUI program problems,  Prev: Charset conversion,  Up: gettext

Additional functions for plural forms
-------------------------------------

The functions of the `gettext' family described so far (and all the
`catgets' functions as well) have one problem in the real world which
have been neglected completely in all existing approaches.  What is
meant here is the handling of plural forms.

   Looking through Unix source code before the time anybody thought
about internationalization (and, sadly, even afterwards) one can often
find code similar to the following:

        printf ("%d file%s deleted", n, n == 1 ? "" : "s");

After the first complaints from people internationalizing the code
people either completely avoided formulations like this or used strings
like `"file(s)"'.  Both look unnatural and should be avoided.  First
tries to solve the problem correctly looked like this:

        if (n == 1)
          printf ("%d file deleted", n);
        else
          printf ("%d files deleted", n);

   But this does not solve the problem.  It helps languages where the
plural form of a noun is not simply constructed by adding an `s' but
that is all.  Once again people fell into the trap of believing the
rules their language is using are universal.  But the handling of plural
forms differs widely between the language families.  For example, Rafal
Maszkowski `<rzm@mat.uni.torun.pl>' reports:

     In Polish we use e.g. plik (file) this way:
          1 plik
          2,3,4 pliki
          5-21 pliko'w
          22-24 pliki
          25-31 pliko'w
     and so on (o' means 8859-2 oacute which should be rather okreska,
     similar to aogonek).

   There are two things which can differ between languages (and even
inside language families);

   * The form how plural forms are built differs.  This is a problem
     with languages which have many irregularities.  German, for
     instance, is a drastic case.  Though English and German are part
     of the same language family (Germanic), the almost regular forming
     of plural noun forms (appending an `s') is hardly found in German.

   * The number of plural forms differ.  This is somewhat surprising for
     those who only have experiences with Romanic and Germanic languages
     since here the number is the same (there are two).

     But other language families have only one form or many forms.  More
     information on this in an extra section.

   The consequence of this is that application writers should not try to
solve the problem in their code.  This would be localization since it is
only usable for certain, hardcoded language environments.  Instead the
extended `gettext' interface should be used.

   These extra functions are taking instead of the one key string two
strings and a numerical argument.  The idea behind this is that using
the numerical argument and the first string as a key, the implementation
can select using rules specified by the translator the right plural
form.  The two string arguments then will be used to provide a return
value in case no message catalog is found (similar to the normal
`gettext' behavior).  In this case the rules for Germanic language is
used and it is assumed that the first string argument is the singular
form, the second the plural form.

   This has the consequence that programs without language catalogs can
display the correct strings only if the program itself is written using
a Germanic language.  This is a limitation but since the GNU C library
(as well as the GNU `gettext' package) are written as part of the GNU
package and the coding standards for the GNU project require program
being written in English, this solution nevertheless fulfills its
purpose.

 - Function: char * ngettext (const char *MSGID1, const char *MSGID2,
          unsigned long int N)
     The `ngettext' function is similar to the `gettext' function as it
     finds the message catalogs in the same way.  But it takes two
     extra arguments.  The MSGID1 parameter must contain the singular
     form of the string to be converted.  It is also used as the key
     for the search in the catalog.  The MSGID2 parameter is the plural
     form.  The parameter N is used to determine the plural form.  If no
     message catalog is found MSGID1 is returned if `n == 1', otherwise
     `msgid2'.

     An example for the use of this function is:

          printf (ngettext ("%d file removed", "%d files removed", n), n);

     Please note that the numeric value N has to be passed to the
     `printf' function as well.  It is not sufficient to pass it only to
     `ngettext'.

 - Function: char * dngettext (const char *DOMAIN, const char *MSGID1,
          const char *MSGID2, unsigned long int N)
     The `dngettext' is similar to the `dgettext' function in the way
     the message catalog is selected.  The difference is that it takes
     two extra parameter to provide the correct plural form.  These two
     parameters are handled in the same way `ngettext' handles them.

 - Function: char * dcngettext (const char *DOMAIN, const char *MSGID1,
          const char *MSGID2, unsigned long int N, int CATEGORY)
     The `dcngettext' is similar to the `dcgettext' function in the way
     the message catalog is selected.  The difference is that it takes
     two extra parameter to provide the correct plural form.  These two
     parameters are handled in the same way `ngettext' handles them.

   Now, how do these functions solve the problem of the plural forms?
Without the input of linguists (which was not available) it was not
possible to determine whether there are only a few different forms in
which plural forms are formed or whether the number can increase with
every new supported language.

   Therefore the solution implemented is to allow the translator to
specify the rules of how to select the plural form.  Since the formula
varies with every language this is the only viable solution except for
hardcoding the information in the code (which still would require the
possibility of extensions to not prevent the use of new languages).

   The information about the plural form selection has to be stored in
the header entry of the PO file (the one with the empty `msgid' string).
The plural form information looks like this:

     Plural-Forms: nplurals=2; plural=n == 1 ? 0 : 1;

   The `nplurals' value must be a decimal number which specifies how
many different plural forms exist for this language.  The string
following `plural' is an expression which is using the C language
syntax.  Exceptions are that no negative numbers are allowed, numbers
must be decimal, and the only variable allowed is `n'.  This expression
will be evaluated whenever one of the functions `ngettext',
`dngettext', or `dcngettext' is called.  The numeric value passed to
these functions is then substituted for all uses of the variable `n' in
the expression.  The resulting value then must be greater or equal to
zero and smaller than the value given as the value of `nplurals'.

The following rules are known at this point.  The language with families
are listed.  But this does not necessarily mean the information can be
generalized for the whole family (as can be easily seen in the table
below).(1)

Only one form:
     Some languages only require one single form.  There is no
     distinction between the singular and plural form.  An appropriate
     header entry would look like this:

          Plural-Forms: nplurals=1; plural=0;

     Languages with this property include:

    Finno-Ugric family
          Hungarian

    Asian family
          Japanese, Korean

    Turkic/Altaic family
          Turkish

Two forms, singular used for one only
     This is the form used in most existing programs since it is what
     English is using.  A header entry would look like this:

          Plural-Forms: nplurals=2; plural=n != 1;

     (Note: this uses the feature of C expressions that boolean
     expressions have to value zero or one.)

     Languages with this property include:

    Germanic family
          Danish, Dutch, English, Faroese, German, Norwegian, Swedish

    Finno-Ugric family
          Estonian, Finnish

    Latin/Greek family
          Greek

    Semitic family
          Hebrew

    Romanic family
          Italian, Portuguese, Spanish

    Artificial
          Esperanto

Two forms, singular used for zero and one
     Exceptional case in the language family.  The header entry would
     be:

          Plural-Forms: nplurals=2; plural=n>1;

     Languages with this property include:

    Romanic family
          French, Brazilian Portuguese

Three forms, special case for zero
     The header entry would be:

          Plural-Forms: nplurals=3; plural=n%10==1 && n%100!=11 ? 0 : n != 0 ? 1 : 2;

     Languages with this property include:

    Baltic family
          Latvian

Three forms, special cases for one and two
     The header entry would be:

          Plural-Forms: nplurals=3; plural=n==1 ? 0 : n==2 ? 1 : 2;

     Languages with this property include:

    Celtic
          Gaeilge (Irish)

Three forms, special case for numbers ending in 1[2-9]
     The header entry would look like this:

          Plural-Forms: nplurals=3; \
              plural=n%10==1 && n%100!=11 ? 0 : \
                     n%10>=2 && (n%100<10 || n%100>=20) ? 1 : 2;

     Languages with this property include:

    Baltic family
          Lithuanian

Three forms, special cases for numbers ending in 1 and 2, 3, 4, except those ending in 1[1-4]
     The header entry would look like this:

          Plural-Forms: nplurals=3; \
              plural=n%10==1 && n%100!=11 ? 0 : \
                     n%10>=2 && n%10<=4 && (n%100<10 || n%100>=20) ? 1 : 2;

     Languages with this property include:

    Slavic family
          Croatian, Czech, Russian, Ukrainian

Three forms, special cases for 1 and 2, 3, 4
     The header entry would look like this:

          Plural-Forms: nplurals=3; \
              plural=(n==1) ? 0 : (n>=2 && n<=4) ? 1 : 2;

     Languages with this property include:

    Slavic family
          Slovak

Three forms, special case for one and some numbers ending in 2, 3, or 4
     The header entry would look like this:

          Plural-Forms: nplurals=3; \
              plural=n==1 ? 0 : \
                     n%10>=2 && n%10<=4 && (n%100<10 || n%100>=20) ? 1 : 2;

     Languages with this property include:

    Slavic family
          Polish

Four forms, special case for one and all numbers ending in 02, 03, or 04
     The header entry would look like this:

          Plural-Forms: nplurals=4; \
              plural=n%100==1 ? 0 : n%100==2 ? 1 : n%100==3 || n%100==4 ? 2 : 3;

     Languages with this property include:

    Slavic family
          Slovenian

   ---------- Footnotes ----------

   (1) Additions are welcome.  Send appropriate information to
<bug-glibc-manual@gnu.org>.


File: gettext.info,  Node: GUI program problems,  Next: Optimized gettext,  Prev: Plural forms,  Up: gettext

How to use `gettext' in GUI programs
------------------------------------

One place where the `gettext' functions, if used normally, have big
problems is within programs with graphical user interfaces (GUIs).  The
problem is that many of the strings which have to be translated are very
short.  They have to appear in pull-down menus which restricts the
length.  But strings which are not containing entire sentences or at
least large fragments of a sentence may appear in more than one
situation in the program but might have different translations.  This is
especially true for the one-word strings which are frequently used in
GUI programs.

   As a consequence many people say that the `gettext' approach is
wrong and instead `catgets' should be used which indeed does not have
this problem.  But there is a very simple and powerful method to handle
these kind of problems with the `gettext' functions.

As as example consider the following fictional situation.  A GUI program
has a menu bar with the following entries:

     +------------+------------+--------------------------------------+
     | File       | Printer    |                                      |
     +------------+------------+--------------------------------------+
     | Open     | | Select   |
     | New      | | Open     |
     +----------+ | Connect  |
                  +----------+

   To have the strings `File', `Printer', `Open', `New', `Select', and
`Connect' translated there has to be at some point in the code a call
to a function of the `gettext' family.  But in two places the string
passed into the function would be `Open'.  The translations might not
be the same and therefore we are in the dilemma described above.

   One solution to this problem is to artificially enlengthen the
strings to make them unambiguous.  But what would the program do if no
translation is available?  The enlengthened string is not what should be
printed.  So we should use a little bit modified version of the
functions.

   To enlengthen the strings a uniform method should be used.  E.g., in
the example above the strings could be chosen as

     Menu|File
     Menu|Printer
     Menu|File|Open
     Menu|File|New
     Menu|Printer|Select
     Menu|Printer|Open
     Menu|Printer|Connect

   Now all the strings are different and if now instead of `gettext'
the following little wrapper function is used, everything works just
fine:

       char *
       sgettext (const char *msgid)
       {
         char *msgval = gettext (msgid);
         if (msgval == msgid)
           msgval = strrchr (msgid, '|') + 1;
         return msgval;
       }

   What this little function does is to recognize the case when no
translation is available.  This can be done very efficiently by a
pointer comparison since the return value is the input value.  If there
is no translation we know that the input string is in the format we used
for the Menu entries and therefore contains a `|' character.  We simply
search for the last occurrence of this character and return a pointer
to the character following it.  That's it!

   If one now consistently uses the enlengthened string form and
replaces the `gettext' calls with calls to `sgettext' (this is normally
limited to very few places in the GUI implementation) then it is
possible to produce a program which can be internationalized.

   The other `gettext' functions (`dgettext', `dcgettext' and the
`ngettext' equivalents) can and should have corresponding functions as
well which look almost identical, except for the parameters and the
call to the underlying function.

   Now there is of course the question why such functions do not exist
in the GNU gettext package?  There are two parts of the answer to this
question.

   * They are easy to write and therefore can be provided by the
     project they are used in.  This is not an answer by itself and
     must be seen together with the second part which is:

   * There is no way the gettext package can contain a version which
     can work everywhere.  The problem is the selection of the
     character to separate the prefix from the actual string in the
     enlenghtened string.  The examples above used `|' which is a quite
     good choice because it resembles a notation frequently used in
     this context and it also is a character not often used in message
     strings.

     But what if the character is used in message strings?  Or if the
     chose character is not available in the character set on the
     machine one compiles (e.g., `|' is not required to exist for
     ISO C; this is why the `iso646.h' file exists in ISO C programming
     environments).

   There is only one more comment to be said.  The wrapper function
above requires that the translations strings are not enlengthened
themselves.  This is only logical.  There is no need to disambiguate
the strings (since they are never used as keys for a search) and one
also saves quite some memory and disk space by doing this.


File: gettext.info,  Node: Optimized gettext,  Prev: GUI program problems,  Up: gettext

Optimization of the *gettext functions
--------------------------------------

At this point of the discussion we should talk about an advantage of the
GNU `gettext' implementation.  Some readers might have pointed out that
an internationalized program might have a poor performance if some
string has to be translated in an inner loop.  While this is unavoidable
when the string varies from one run of the loop to the other it is
simply a waste of time when the string is always the same.  Take the
following example:

     {
       while (...)
         {
           puts (gettext ("Hello world"));
         }
     }

When the locale selection does not change between two runs the resulting
string is always the same.  One way to use this is:

     {
       str = gettext ("Hello world");
       while (...)
         {
           puts (str);
         }
     }

But this solution is not usable in all situation (e.g. when the locale
selection changes) nor does it lead to legible code.

   For this reason, GNU `gettext' caches previous translation results.
When the same translation is requested twice, with no new message
catalogs being loaded in between, `gettext' will, the second time, find
the result through a single cache lookup.


File: gettext.info,  Node: Comparison,  Next: Using libintl.a,  Prev: gettext,  Up: Programmers

Comparing the Two Interfaces
============================

The following discussion is perhaps a little bit colored.  As said
above we implemented GNU `gettext' following the Uniforum proposal and
this surely has its reasons.  But it should show how we came to this
decision.

   First we take a look at the developing process.  When we write an
application using NLS provided by `gettext' we proceed as always.  Only
when we come to a string which might be seen by the users and thus has
to be translated we use `gettext("...")' instead of `"..."'.  At the
beginning of each source file (or in a central header file) we define

     #define gettext(String) (String)

   Even this definition can be avoided when the system supports the
`gettext' function in its C library.  When we compile this code the
result is the same as if no NLS code is used.  When  you take a look at
the GNU `gettext' code you will see that we use `_("...")' instead of
`gettext("...")'.  This reduces the number of additional characters per
translatable string to _3_ (in words: three).

   When now a production version of the program is needed we simply
replace the definition

     #define _(String) (String)

by

     #include <libintl.h>
     #define _(String) gettext (String)

Additionally we run the program `xgettext' on all source code file
which contain translatable strings and that's it: we have a running
program which does not depend on translations to be available, but which
can use any that becomes available.

   The same procedure can be done for the `gettext_noop' invocations
(*note Special cases::).  One usually defines `gettext_noop' as a no-op
macro.  So you should consider the following code for your project:

     #define gettext_noop(String) String
     #define N_(String) gettext_noop (String)

   `N_' is a short form similar to `_'.  The `Makefile' in the `po/'
directory of GNU `gettext' knows by default both of the mentioned short
forms so you are invited to follow this proposal for your own ease.

   Now to `catgets'.  The main problem is the work for the programmer.
Every time he comes to a translatable string he has to define a number
(or a symbolic constant) which has also be defined in the message
catalog file.  He also has to take care for duplicate entries,
duplicate message IDs etc.  If he wants to have the same quality in the
message catalog as the GNU `gettext' program provides he also has to
put the descriptive comments for the strings and the location in all
source code files in the message catalog.  This is nearly a Mission:
Impossible.

   But there are also some points people might call advantages speaking
for `catgets'.  If you have a single word in a string and this string
is used in different contexts it is likely that in one or the other
language the word has different translations.  Example:

     printf ("%s: %d", gettext ("number"), number_of_errors)
     
     printf ("you should see %d %s", number_count,
             number_count == 1 ? gettext ("number") : gettext ("numbers"))

   Here we have to translate two times the string `"number"'.  Even if
you do not speak a language beside English it might be possible to
recognize that the two words have a different meaning.  In German the
first appearance has to be translated to `"Anzahl"' and the second to
`"Zahl"'.

   Now you can say that this example is really esoteric.  And you are
right!  This is exactly how we felt about this problem and decide that
it does not weight that much.  The solution for the above problem could
be very easy:

     printf ("%s %d", gettext ("number:"), number_of_errors)
     
     printf (number_count == 1 ? gettext ("you should see %d number")
                               : gettext ("you should see %d numbers"),
             number_count)

   We believe that we can solve all conflicts with this method.  If it
is difficult one can also consider changing one of the conflicting
string a little bit.  But it is not impossible to overcome.

   `catgets' allows same original entry to have different translations,
but `gettext' has another, scalable approach for solving ambiguities of
this kind: *Note Ambiguities::.


File: gettext.info,  Node: Using libintl.a,  Next: gettext grok,  Prev: Comparison,  Up: Programmers

Using libintl.a in own programs
===============================

Starting with version 0.9.4 the library `libintl.h' should be
self-contained.  I.e., you can use it in your own programs without
providing additional functions.  The `Makefile' will put the header and
the library in directories selected using the `$(prefix)'.


File: gettext.info,  Node: gettext grok,  Next: Temp Programmers,  Prev: Using libintl.a,  Up: Programmers

Being a `gettext' grok
======================

To fully exploit the functionality of the GNU `gettext' library it is
surely helpful to read the source code.  But for those who don't want
to spend that much time in reading the (sometimes complicated) code here
is a list comments:

   * Changing the language at runtime

     For interactive programs it might be useful to offer a selection
     of the used language at runtime.  To understand how to do this one
     need to know how the used language is determined while executing
     the `gettext' function.  The method which is presented here only
     works correctly with the GNU implementation of the `gettext'
     functions.

     In the function `dcgettext' at every call the current setting of
     the highest priority environment variable is determined and used.
     Highest priority means here the following list with decreasing
     priority:

       1. `LANGUAGE'

       2. `LC_ALL'

       3. `LC_xxx', according to selected locale

       4. `LANG'

     Afterwards the path is constructed using the found value and the
     translation file is loaded if available.

     What happens now when the value for, say, `LANGUAGE' changes?
     According to the process explained above the new value of this
     variable is found as soon as the `dcgettext' function is called.
     But this also means the (perhaps) different message catalog file
     is loaded.  In other words: the used language is changed.

     But there is one little hook.  The code for gcc-2.7.0 and up
     provides some optimization.  This optimization normally prevents
     the calling of the `dcgettext' function as long as no new catalog
     is loaded.  But if `dcgettext' is not called the program also
     cannot find the `LANGUAGE' variable be changed (*note Optimized
     gettext::).  A solution for this is very easy.  Include the
     following code in the language switching function.

            /* Change language.  */
            setenv ("LANGUAGE", "fr", 1);
          
            /* Make change known.  */
            {
              extern int  _nl_msg_cat_cntr;
              ++_nl_msg_cat_cntr;
            }

     The variable `_nl_msg_cat_cntr' is defined in `loadmsgcat.c'.  You
     don't need to know what this is for.  But it can be used to detect
     whether a `gettext' implementation is GNU gettext and not non-GNU
     system's native gettext implementation.



File: gettext.info,  Node: Temp Programmers,  Prev: gettext grok,  Up: Programmers

Temporary Notes for the Programmers Chapter
===========================================

* Menu:

* Temp Implementations::        Temporary - Two Possible Implementations
* Temp catgets::                Temporary - About `catgets'
* Temp WSI::                    Temporary - Why a single implementation
* Temp Notes::                  Temporary - Notes


File: gettext.info,  Node: Temp Implementations,  Next: Temp catgets,  Prev: Temp Programmers,  Up: Temp Programmers

Temporary - Two Possible Implementations
----------------------------------------

There are two competing methods for language independent messages: the
X/Open `catgets' method, and the Uniforum `gettext' method.  The
`catgets' method indexes messages by integers; the `gettext' method
indexes them by their English translations.  The `catgets' method has
been around longer and is supported by more vendors.  The `gettext'
method is supported by Sun, and it has been heard that the COSE
multi-vendor initiative is supporting it.  Neither method is a POSIX
standard; the POSIX.1 committee had a lot of disagreement in this area.

   Neither one is in the POSIX standard.  There was much disagreement
in the POSIX.1 committee about using the `gettext' routines vs.
`catgets' (XPG).  In the end the committee couldn't agree on anything,
so no messaging system was included as part of the standard.  I believe
the informative annex of the standard includes the XPG3 messaging
interfaces, "...as an example of a messaging system that has been
implemented..."

   They were very careful not to say anywhere that you should use one
set of interfaces over the other.  For more on this topic please see
the Programming for Internationalization FAQ.


File: gettext.info,  Node: Temp catgets,  Next: Temp WSI,  Prev: Temp Implementations,  Up: Temp Programmers

Temporary - About `catgets'
---------------------------

There have been a few discussions of late on the use of `catgets' as a
base.  I think it important to present both sides of the argument and
hence am opting to play devil's advocate for a little bit.

   I'll not deny the fact that `catgets' could have been designed a lot
better.  It currently has quite a number of limitations and these have
already been pointed out.

   However there is a great deal to be said for consistency and
standardization.  A common recurring problem when writing Unix software
is the myriad portability problems across Unix platforms.  It seems as
if every Unix vendor had a look at the operating system and found parts
they could improve upon.  Undoubtedly, these modifications are probably
innovative and solve real problems.  However, software developers have
a hard time keeping up with all these changes across so many platforms.

   And this has prompted the Unix vendors to begin to standardize their
systems.  Hence the impetus for Spec1170.  Every major Unix vendor has
committed to supporting this standard and every Unix software developer
waits with glee the day they can write software to this standard and
simply recompile (without having to use autoconf) across different
platforms.

   As I understand it, Spec1170 is roughly based upon version 4 of the
X/Open Portability Guidelines (XPG4).  Because `catgets' and friends
are defined in XPG4, I'm led to believe that `catgets' is a part of
Spec1170 and hence will become a standardized component of all Unix
systems.


File: gettext.info,  Node: Temp WSI,  Next: Temp Notes,  Prev: Temp catgets,  Up: Temp Programmers

Temporary - Why a single implementation
---------------------------------------

Now it seems kind of wasteful to me to have two different systems
installed for accessing message catalogs.  If we do want to remedy
`catgets' deficiencies why don't we try to expand `catgets' (in a
compatible manner) rather than implement an entirely new system.
Otherwise, we'll end up with two message catalog access systems
installed with an operating system - one set of routines for packages
using GNU `gettext' for their internationalization, and another set of
routines (catgets) for all other software.  Bloated?

   Supposing another catalog access system is implemented.  Which do we
recommend?  At least for Linux, we need to attract as many software
developers as possible.  Hence we need to make it as easy for them to
port their software as possible.  Which means supporting `catgets'.  We
will be implementing the `libintl' code within our `libc', but does
this mean we also have to incorporate another message catalog access
scheme within our `libc' as well?  And what about people who are going
to be using the `libintl' + non-`catgets' routines.  When they port
their software to other platforms, they're now going to have to include
the front-end (`libintl') code plus the back-end code (the non-`catgets'
access routines) with their software instead of just including the
`libintl' code with their software.

   Message catalog support is however only the tip of the iceberg.
What about the data for the other locale categories.  They also have a
number of deficiencies.  Are we going to abandon them as well and
develop another duplicate set of routines (should `libintl' expand
beyond message catalog support)?

   Like many parts of Unix that can be improved upon, we're stuck with
balancing compatibility with the past with useful improvements and
innovations for the future.


File: gettext.info,  Node: Temp Notes,  Prev: Temp WSI,  Up: Temp Programmers

Temporary - Notes
-----------------

X/Open agreed very late on the standard form so that many
implementations differ from the final form.  Both of my system (old
Linux catgets and Ultrix-4) have a strange variation.

   OK.  After incorporating the last changes I have to spend some time
on making the GNU/Linux `libc' `gettext' functions.  So in future
Solaris is not the only system having `gettext'.


File: gettext.info,  Node: Translators,  Next: Maintainers,  Prev: Programmers,  Up: Top

The Translator's View
*********************

* Menu:

* Trans Intro 0::               Introduction 0
* Trans Intro 1::               Introduction 1
* Discussions::                 Discussions
* Organization::                Organization
* Information Flow::            Information Flow
* Prioritizing messages::       How to find which messages to translate first


File: gettext.info,  Node: Trans Intro 0,  Next: Trans Intro 1,  Prev: Translators,  Up: Translators

Introduction 0
==============

Free software is going international!  The Translation Project is a way
to get maintainers, translators and users all together, so free software
will gradually become able to speak many native languages.

   The GNU `gettext' tool set contains _everything_ maintainers need
for internationalizing their packages for messages.  It also contains
quite useful tools for helping translators at localizing messages to
their native language, once a package has already been
internationalized.

   To achieve the Translation Project, we need many interested people
who like their own language and write it well, and who are also able to
synergize with other translators speaking the same language.  If you'd
like to volunteer to _work_ at translating messages, please send mail
to your translating team.

   Each team has its own mailing list, courtesy of Linux International.
You may reach your translating team at the address `LL@li.org',
replacing LL by the two-letter ISO 639 code for your language.
Language codes are _not_ the same as country codes given in ISO 3166.
The following translating teams exist:

     Chinese `zh', Czech `cs', Danish `da', Dutch `nl', Esperanto `eo',
     Finnish `fi', French `fr', Irish `ga', German `de', Greek `el',
     Italian `it', Japanese `ja', Indonesian `in', Norwegian `no',
     Polish `pl', Portuguese `pt', Russian `ru', Spanish `es', Swedish
     `sv' and Turkish `tr'.

For example, you may reach the Chinese translating team by writing to
`zh@li.org'.  When you become a member of the translating team for your
own language, you may subscribe to its list.  For example, Swedish
people can send a message to `sv-request@li.org', having this message
body:

     subscribe

   Keep in mind that team members should be interested in _working_ at
translations, or at solving translational difficulties, rather than
merely lurking around.  If your team does not exist yet and you want to
start one, please write to `translation@iro.umontreal.ca'; you will
then reach the coordinator for all translator teams.

   A handful of GNU packages have already been adapted and provided
with message translations for several languages.  Translation teams
have begun to organize, using these packages as a starting point.  But
there are many more packages and many languages for which we have no
volunteer translators.  If you would like to volunteer to work at
translating messages, please send mail to
`translation@iro.umontreal.ca' indicating what language(s) you can work
on.


File: gettext.info,  Node: Trans Intro 1,  Next: Discussions,  Prev: Trans Intro 0,  Up: Translators

Introduction 1
==============

This is now official, GNU is going international!  Here is the
announcement submitted for the January 1995 GNU Bulletin:

     A handful of GNU packages have already been adapted and provided
     with message translations for several languages.  Translation
     teams have begun to organize, using these packages as a starting
     point.  But there are many more packages and many languages for
     which we have no volunteer translators.  If you'd like to
     volunteer to work at translating messages, please send mail to
     `translation@iro.umontreal.ca' indicating what language(s) you can
     work on.

   This document should answer many questions for those who are curious
about the process or would like to contribute.  Please at least skim
over it, hoping to cut down a little of the high volume of e-mail
generated by this collective effort towards internationalization of
free software.

   Most free programming which is widely shared is done in English, and
currently, English is used as the main communicating language between
national communities collaborating to free software.  This very document
is written in English.  This will not change in the foreseeable future.

   However, there is a strong appetite from national communities for
having more software able to write using national language and habits,
and there is an on-going effort to modify free software in such a way
that it becomes able to do so.  The experiments driven so far raised an
enthusiastic response from pretesters, so we believe that
internationalization of free software is dedicated to succeed.

   For suggestion clarifications, additions or corrections to this
document, please e-mail to `translation@iro.umontreal.ca'.


File: gettext.info,  Node: Discussions,  Next: Organization,  Prev: Trans Intro 1,  Up: Translators

Discussions
===========

Facing this internationalization effort, a few users expressed their
concerns.  Some of these doubts are presented and discussed, here.

   * Smaller groups

     Some languages are not spoken by a very large number of people, so
     people speaking them sometimes consider that there may not be all
     that much demand such versions of free software packages.
     Moreover, many people being _into computers_, in some countries,
     generally seem to prefer English versions of their software.

     On the other end, people might enjoy their own language a lot, and
     be very motivated at providing to themselves the pleasure of
     having their beloved free software speaking their mother tongue.
     They do themselves a personal favor, and do not pay that much
     attention to the number of people benefiting of their work.

   * Misinterpretation

     Other users are shy to push forward their own language, seeing in
     this some kind of misplaced propaganda.  Someone thought there
     must be some users of the language over the networks pestering
     other people with it.

     But any spoken language is worth localization, because there are
     people behind the language for whom the language is important and
     dear to their hearts.

   * Odd translations

     The biggest problem is to find the right translations so that
     everybody can understand the messages.  Translations are usually a
     little odd.  Some people get used to English, to the extent they
     may find translations into their own language "rather pushy,
     obnoxious and sometimes even hilarious."  As a French speaking
     man, I have the experience of those instruction manuals for goods,
     so poorly translated in French in Korea or Taiwan...

     The fact is that we sometimes have to create a kind of national
     computer culture, and this is not easy without the collaboration of
     many people liking their mother tongue.  This is why translations
     are better achieved by people knowing and loving their own
     language, and ready to work together at improving the results they
     obtain.

   * Dependencies over the GPL or LGPL

     Some people wonder if using GNU `gettext' necessarily brings their
     package under the protective wing of the GNU General Public
     License or the GNU Library General Public License, when they do
     not want to make their program free, or want other kinds of
     freedom.  The simplest answer is "normally not".

     The `gettext-runtime' part of GNU `gettext', i.e. the contents of
     `libintl', is covered by the GNU Library General Public License.
     The `gettext-tools' part of GNU `gettext', i.e. the rest of the
     GNU `gettext' package, is covered by the GNU General Public
     License.

     The mere marking of localizable strings in a package, or
     conditional inclusion of a few lines for initialization, is not
     really including GPL'ed or LGPL'ed code.  However, since the
     localization routines in `libintl' are under the LGPL, the LGPL
     needs to be considered.  It gives the right to distribute the
     complete unmodified source of `libintl' even with non-free
     programs.  It also gives the right to use `libintl' as a shared
     library, even for non-free programs.  But it gives the right to
     use `libintl' as a static library or to incorporate `libintl' into
     another library only to free software.



File: gettext.info,  Node: Organization,  Next: Information Flow,  Prev: Discussions,  Up: Translators

Organization
============

On a larger scale, the true solution would be to organize some kind of
fairly precise set up in which volunteers could participate.  I gave
some thought to this idea lately, and realize there will be some touchy
points.  I thought of writing to Richard Stallman to launch such a
project, but feel it might be good to shake out the ideas between
ourselves first.  Most probably that Linux International has some
experience in the field already, or would like to orchestrate the
volunteer work, maybe.  Food for thought, in any case!

   I guess we have to setup something early, somehow, that will help
many possible contributors of the same language to interlock and avoid
work duplication, and further be put in contact for solving together
problems particular to their tongue (in most languages, there are many
difficulties peculiar to translating technical English).  My Swedish
contributor acknowledged these difficulties, and I'm well aware of them
for French.

   This is surely not a technical issue, but we should manage so the
effort of locale contributors be maximally useful, despite the national
team layer interface between contributors and maintainers.

   The Translation Project needs some setup for coordinating language
coordinators.  Localizing evolving programs will surely become a
permanent and continuous activity in the free software community, once
well started.  The setup should be minimally completed and tested
before GNU `gettext' becomes an official reality.  The e-mail address
`translation@iro.umontreal.ca' has been setup for receiving offers from
volunteers and general e-mail on these topics.  This address reaches
the Translation Project coordinator.

* Menu:

* Central Coordination::        Central Coordination
* National Teams::              National Teams
* Mailing Lists::               Mailing Lists


File: gettext.info,  Node: Central Coordination,  Next: National Teams,  Prev: Organization,  Up: Organization

Central Coordination
--------------------

I also think GNU will need sooner than it thinks, that someone setup a
way to organize and coordinate these groups.  Some kind of group of
groups.  My opinion is that it would be good that GNU delegates this
task to a small group of collaborating volunteers, shortly.  Perhaps in
`gnu.announce' a list of this national committee's can be published.

   My role as coordinator would simply be to refer to Ulrich any German
speaking volunteer interested to localization of free software
packages, and maybe helping national groups to initially organize,
while maintaining national registries for until national groups are
ready to take over.  In fact, the coordinator should ease volunteers to
get in contact with one another for creating national teams, which
should then select one coordinator per language, or country
(regionalized language).  If well done, the coordination should be
useful without being an overwhelming task, the time to put delegations
in place.


File: gettext.info,  Node: National Teams,  Next: Mailing Lists,  Prev: Central Coordination,  Up: Organization

National Teams
--------------

I suggest we look for volunteer coordinators/editors for individual
languages.  These people will scan contributions of translation files
for various programs, for their own languages, and will ensure high and
uniform standards of diction.

   From my current experience with other people in these days, those who
provide localizations are very enthusiastic about the process, and are
more interested in the localization process than in the program they
localize, and want to do many programs, not just one.  This seems to
confirm that having a coordinator/editor for each language is a good
idea.

   We need to choose someone who is good at writing clear and concise
prose in the language in question.  That is hard--we can't check it
ourselves.  So we need to ask a few people to judge each others'
writing and select the one who is best.

   I announce my prerelease to a few dozen people, and you would not
believe all the discussions it generated already.  I shudder to think
what will happen when this will be launched, for true, officially,
world wide.  Who am I to arbitrate between two Czekolsovak users
contradicting each other, for example?

   I assume that your German is not much better than my French so that
I would not be able to judge about these formulations.  What I would
suggest is that for each language there is a group for people who
maintain the PO files and judge about changes.  I suspect there will be
cultural differences between how such groups of people will behave.
Some will have relaxed ways, reach consensus easily, and have anyone of
the group relate to the maintainers, while others will fight to death,
organize heavy administrations up to national standards, and use strict
channels.

   The German team is putting out a good example.  Right now, they are
maybe half a dozen people revising translations of each other and
discussing the linguistic issues.  I do not even have all the names.
Ulrich Drepper is taking care of coordinating the German team.  He
subscribed to all my pretest lists, so I do not even have to warn him
specifically of incoming releases.

   I'm sure, that is a good idea to get teams for each language working
on translations.  That will make the translations better and more
consistent.

* Menu:

* Sub-Cultures::                Sub-Cultures
* Organizational Ideas::        Organizational Ideas


File: gettext.info,  Node: Sub-Cultures,  Next: Organizational Ideas,  Prev: National Teams,  Up: National Teams

Sub-Cultures
............

Taking French for example, there are a few sub-cultures around computers
which developed diverging vocabularies.  Picking volunteers here and
there without addressing this problem in an organized way, soon in the
project, might produce a distasteful mix of internationalized programs,
and possibly trigger endless quarrels among those who really care.

   Keeping some kind of unity in the way French localization of
internationalized programs is achieved is a difficult (and delicate)
job.  Knowing the latin character of French people (:-), if we take this
the wrong way, we could end up nowhere, or spoil a lot of energies.
Maybe we should begin to address this problem seriously _before_ GNU
`gettext' become officially published.  And I suspect that this means
soon!


File: gettext.info,  Node: Organizational Ideas,  Prev: Sub-Cultures,  Up: National Teams

Organizational Ideas
....................

I expect the next big changes after the official release.  Please note
that I use the German translation of the short GPL message.  We need to
set a few good examples before the localization goes out for true in
the free software community.  Here are a few points to discuss:

   * Each group should have one FTP server (at least one master).

   * The files on the server should reflect the latest version (of
     course!) and it should also contain a RCS directory with the
     corresponding archives (I don't have this now).

   * There should also be a ChangeLog file (this is more useful than the
     RCS archive but can be generated automatically from the later by
     Emacs).

   * A "core group" should judge about questionable changes (for now
     this group consists solely by me but I ask some others
     occasionally; this also seems to work).



File: gettext.info,  Node: Mailing Lists,  Prev: National Teams,  Up: Organization

Mailing Lists
-------------

If we get any inquiries about GNU `gettext', send them on to:

     `translation@iro.umontreal.ca'

   The `*-pretest' lists are quite useful to me, maybe the idea could
be generalized to many GNU, and non-GNU packages.  But each maintainer
his/her way!

   Franc,ois, we have a mechanism in place here at `gnu.ai.mit.edu' to
track teams, support mailing lists for them and log members.  We have a
slight preference that you use it.  If this is OK with you, I can get
you clued in.

   Things are changing!  A few years ago, when Daniel Fekete and I
asked for a mailing list for GNU localization, nested at the FSF, we
were politely invited to organize it anywhere else, and so did we.  For
communicating with my pretesters, I later made a handful of mailing
lists located at iro.umontreal.ca and administrated by `majordomo'.
These lists have been _very_ dependable so far...

   I suspect that the German team will organize itself a mailing list
located in Germany, and so forth for other countries.  But before they
organize for true, it could surely be useful to offer mailing lists
located at the FSF to each national team.  So yes, please explain me
how I should proceed to create and handle them.

   We should create temporary mailing lists, one per country, to help
people organize.  Temporary, because once regrouped and structured, it
would be fair the volunteers from country bring back _their_ list in
there and manage it as they want.  My feeling is that, in the long run,
each team should run its own list, from within their country.  There
also should be some central list to which all teams could subscribe as
they see fit, as long as each team is represented in it.

