The setlocale() function

The setlocale() function is the interface to the program's locale. In general, any program that requires the invocation country's conventions should place a call such as:

   #include <locale.h>
   /.../
   setlocale(LC_ALL, "");

LC_COLLATE	sorting information
LC_CTYPE	character classification information
LC_MONETARY	currency printing information
LC_NUMERIC	numeric printing information
LC_TIME	date and time printing information
LC_MESSAGES	message language information

Any of these macros can be passed as the first argument to setlocale() to specify just that category.

The setlocale() function returns the name of the current locale for a given category (or LC_ALL) and serves in an inquiry-only capacity when its second argument is a null pointer. Thus, code along the lines of the following can be used to change the locale or a portion thereof for a limited duration:

   #include <locale.h>
   /.../
   char oloc;
   /.../
   oloc = setlocale(LC_cat, NULL);
   if (setlocale(LC_cat, "new") != 0)
   {
      / use temporarily changed locale /
      (void)setlocale(LC_cat, oloc);
   }