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(gettext.info)Interface to gettext

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The Interface
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   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 return 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 not available the argument itself is returned.
If the argument is `NULL' the result is undefined.

   One things 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.