The facilities in GNU
gettext focus on messages; strings printed
by a program, either directly or via formatting with
When using GNU
gettext, each application has its own
text domain. This is a unique name, such as ‘kpilot’ or ‘gawk’,
that identifies the application.
A complete application may have multiple components—programs written
in C or C++, as well as scripts written in sh or awk.
All of the components use the same text domain.
To make the discussion concrete, assume we're writing an application named guide. Internationalization consists of the following steps, in this order:
"`-F': option required"is a good candidate for translation. A table with strings of option names is not (e.g., gawk's --profile option should remain the same, no matter what the local language).
"guide") to the
gettextlibrary, by calling the
.po) and translations are created and shipped with the application. For example, there might be a fr.po for a French translation.
gettextto use .gmo files in a different directory than the standard one by using the
gettext(). The returned string is the translated string if available, or the original string if not.
In C (or C++), the string marking and dynamic translation lookup
are accomplished by wrapping each string in a call to
printf("%s", gettext("Don't Panic!\n"));
The tools that extract messages from source code pull out all
strings enclosed in calls to
gettext developers, recognizing that typing
‘gettext(...)’ over and over again is both painful and ugly to look
at, use the macro ‘_’ (an underscore) to make things easier:
/* In the standard header file: */ #define _(str) gettext(str) /* In the program text: */ printf("%s", _("Don't Panic!\n"));
This reduces the typing overhead to just three extra characters per string and is considerably easier to read as well.
There are locale categories
for different types of locale-related information.
The defined locale categories that
gettext knows about are:
gettextoperations, but it is possible to supply a different one explicitly, if necessary. (It is almost never necessary to supply a different category.)
/[[:alnum:]]/(see Regexp Operators).
 For some operating systems, the gawk
port doesn't support GNU
Therefore, these features are not available
if you are using one of those operating systems. Sorry.
 Americans use a comma every three decimal places and a period for the decimal point, while many Europeans do exactly the opposite: 1,234.56 versus 1.234,56.