CONVENIENCE FUNCTIONS
     The xlocale API includes a	number of _l suffixed convenience functions.
     These are variants	of standard C functions	that have been modified	to
     take an explicit locale_t parameter as the	final argument or, in the case
     of	variadic functions, as an additional argument directly before the for-
     mat string.  Each of these	functions accepts either NULL or
     LC_GLOBAL_LOCALE.	In these functions, NULL refers	to the C locale,
     rather than the thread's current locale.  If you wish to use the thread's
     current locale, then use the unsuffixed version of	the function.

     These functions are exposed by including <xlocale.h> after	including the
     relevant headers for the standard variant.	 For example, the strtol_l(3)
     function is exposed by including <xlocale.h> after	<stdlib.h>, which
     defines strtol(3).