Gettext
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- The title of this article is incorrect because of technical limitations. The correct title is gettext.
gettext is the GNU internationalization (i18n) library. It is commonly used for writing multilingual programs. The latest version is 0.14.
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Workflow
Programmer
Source code is first modified to use the GNU gettext calls. This is, for most languages, done by wrapping strings that the user will see in the gettext function. To save on typing time, this function is usually aliased to _, so that the C code
printf("My name is %s.\n", my_name);
would become
printf(_("My name is %s.\n"), my_name);
In addition to C, GNU gettext has the following implementations: C++, Objective C, sh script, bash script, Python, GNU CLISP, Emacs Lisp, librep, GNU Smalltalk, Java, GNU awk, Pascal, wxWidgets (through the WxLocale class), YCP (the YaST2 language), Tcl, Perl, PHP, and Pike. Usage is similar to C for most of these.
xgettext is run on the sources to produce a .pot file, or template, which contains a list of all the translatable strings extracted from the sources. For the above, an entry in the .pot file would look like:
#: src/name.c:36 msgid "My name is %s.\n" msgstr ""
Translator
The translator derives a .po file from the template using the msginit program, then fills out the translations. msginit initializes the translations so, for instance, if we wish to create a French language translation, we'd run
msginit --locale=fr --input=name.pot
This will create fr.po. A sample entry would look like
#: src/name.c:36 msgid "My name is %s.\n" msgstr "My name is %s.\n"
The translator will have to edit these, either by hand or with a translation tool like poEdit. When they are done, the entry will look like this:
#: src/name.c:36 msgid "My name is %s.\n" msgstr "Je m'appelle %s.\n"
Finally, the .po files are compiled into binary .mo files with msgfmt. These are now ready for distribution with the software package.
User
The user, on Unix-type systems, sets the environment variable LANGUAGE, and the program will display strings in the selected language, if there is a .mo file for it.
External links
- Gettext homepage (http://www.gnu.org/software/gettext/gettext.html)pl:GNU gettext