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 __
Message catalogs will be expected at the pathnames dirname/locale/category/domainname.mo, where locale is a locale name and category is a locale facet such as LC_MESSAGES.
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 be found.
The following error can occur, among others: