Editing Gettext (section)

===Programming===
[[File:Gettext.svg|thumb|Typical gettext workflow.  The de.po instance on the left shows a "renewing" of translations via msgmerge.]]
The basic interface of gettext is the {{code|gettext(const char*)}} function, which accepts a [[string (computer science)|string]] that the user will see in the original language, usually English. To save typing time and reduce code clutter, this function is commonly [[aliasing (computing)|aliased]] to <code>_</code>:<ref>{{Cite web |date= |title=GNU gettext utilities: How Marks Appear in Sources |url=https://www.gnu.org/software/gettext/manual/gettext.html#How-Marks-Appear-in-Sources |url-status=live |archive-url=https://web.archive.org/web/20240325095308/https://www.gnu.org/software/gettext/manual/gettext.html#How-Marks-Appear-in-Sources |archive-date=2024-03-25 |access-date=2024-04-03 |website=www.gnu.org}}</ref>

<syntaxhighlight lang="C">
printf(gettext("My name is %s.\n"), my_name);
printf(_("My name is %s.\n"), my_name); // same, but shorter
</syntaxhighlight>

<code>gettext()</code> then uses the supplied strings as keys for looking up translations, and will return the original string when no translation is available. This is in contrast to [[POSIX]] <code>catgets()</code>,<ref>{{cite web|url=https://www.gnu.org/software/gettext/manual/html_node/catgets.html |website=gnu.org |title=About catgets |access-date=2017-10-24}}</ref> [[AmigaOS]] <code>GetString()</code>,<ref>{{Cite web |title=AmigaOS Manual: Python Modules and Packages - AmigaOS Documentation Wiki |url=https://wiki.amigaos.net/wiki/AmigaOS_Manual:_Python_Modules_and_Packages#GetString.28.29 |access-date=2023-07-09 |website=wiki.amigaos.net}}</ref> or [[Microsoft Windows]] <code>LoadString()</code>  where a programmatic ID (often an integer) is used. To handle the case where the same original-language text can have different meanings, gettext has functions like <code>cgettext()</code> that accept an additional "context" string.

<code>xgettext</code> is run on the sources to produce a <code>.pot</code> (Portable Object Template) file, which contains a list of all the translatable strings extracted from the sources. Comments starting with <code>///</code> are used to give translators hints, although other prefixes are also configurable to further limit the scope. One such common prefix is <code>TRANSLATORS:</code>.

For example, an input file with a comment might look like:

<syntaxhighlight lang="C">
/// TRANSLATORS: %s contains the user's name as specified in Preferences
printf(_("My name is %s.\n"), my_name);
</syntaxhighlight>

<code>xgettext</code> is run using the command:

 xgettext -c /

The resultant .pot file looks like this with the comment (note that xgettext recognizes the string as a [[C (programming language)|C]]-language [[printf]] format string):
<syntaxhighlight lang="po">
#. TRANSLATORS: %s contains the user's name as specified in Preferences
#, c-format
#: src/name.c:36
msgid "My name is %s.\n"
msgstr ""
</syntaxhighlight>

In POSIX [[shell script]], gettext provides a <code>gettext.sh</code> library one can include that provides the many same functions gettext provides in similar languages.<ref>{{cite web |title=GNU gettext utilities: sh |url=https://www.gnu.org/software/gettext/manual/html_node/sh.html}}</ref> [[GNU bash]] also has a simplified construct <code>$"msgid"</code> for the simple gettext function, although it depends on the C library to provide a <code>gettext()</code> function.<ref>{{cite web |title=GNU gettext utilities: bash |url=https://www.gnu.org/software/gettext/manual/html_node/bash.html}}</ref>