The bindtextdomain function sets the base directory of the hierarchy
containing message catalogs for a given message domain.
A message domain is a set of translatable msgid messages. Usually,
every software package has its own message domain. The need for calling
bindtextdomain arises because packages are not always installed with
the same prefix as the <libintl.h> header and the libc/libintl libraries.
Message catalogs will be expected at the pathnames
where locale is a locale name and category is a locale facet such
domainname must be a non-empty string.
If dirname is not NULL, the base directory for message catalogs belonging
to domain domainname is set to dirname. The function makes copies
of the argument strings as needed. If the program wishes to call the
chdir function, it is important that dirname be an absolute
pathname; otherwise it cannot be guaranteed that the message catalogs will
If dirname is NULL, the function returns the previously set base
directory for domain domainname.
If successful, the bindtextdomain function returns the current base
directory for domain domainname, after possibly changing it. The
resulting string is valid until the next bindtextdomain call for the
same domainname and must not be modified or freed. If a memory allocation
failure occurs, it sets errno to ENOMEM and returns NULL.
The following error can occur, among others:
Not enough memory available.
The return type ought to be const char *, but is char * to avoid
warnings in C code predating ANSI C.