c/locale/LC categories

Each of the above macro constants expand to integer constant expressions with distinct values that are suitable for use as the first argument of setlocale.

Additional macro constants, with names that begin with followed by at least one uppercase letter, may be defined in. For example, the POSIX specification requires LC_MESSAGES (which controls, among other things, perror and strerror), ISO/IEC 30112:2014 (2014 draft) additionally defines LC_IDENTIFICATION, LC_XLITERATE, LC_NAME, LC_ADDRESS, LC_TELEPHONE, LC_PAPER, LC_MEASUREMENT, and LC_KEYBOARD, which are supported by the GNU C library (except for LC_XLITERATE)