Internationalization routines are useful for creating different versions of a program for international markets. These routines are declared in the header file LOCALE.H, except for strftime, which is declared in TIME.H.
| Routine | Use |
| localeconv | Sets a structure with appropriate values for formatting numeric quantities |
| setlocale | Selects the appropriate locale for the program |
| strcoll | Compares strings using locale-specific information |
| strftime | Formats a date and time string |
| strxfrm | Transforms a string based on locale-specific information |
Currently only the "C" locale is supported by Microsoft C/C++.