C localization functions

Overview of functions

C localization functions and types are defined in ( header in C++).

Criticism

C standard localization functions are criticized because the localization state is stored globally. This means that in a given program all operations involving a locale can use only one locale at a time. As a result, it is very difficult to implement programs that use more than one locale.

The functions alter the behavior of printf/scanf/strtod which are often used to write saved data to a file or to other programs. The result is that a saved file in one locale will not be readable in another locale, or not be readable at all due to assumptions such as "numbers end at comma characters". Most large-scale software forces the locale to "C" (or another fixed value) to work around these problems.

Example

#include <locale.h>
#include <stdio.h>
#include <stdlib.h>

int main(void) {
    /* Locale is set to "C" before this. This call sets it
       to the "current locale" by reading environment variables: */
    setlocale(LC_ALL, "");

    const struct lconv* const currentlocale = localeconv();

    printf("In the current locale, the default currency symbol is: %s\n", currentlocale->currency_symbol);

    return EXIT_SUCCESS;
}

References

References

1. "ISO/IEC 9899:1999 specification".
2. Prata, Stephen. (2004). "C primer plus". Sams Publishing.
3. (12 April 2011). "ISO/IEC 9899:201x".
4. "locale.h". infosys.
5. "openbsd/src".
6. (1996). "The Standard C Locale and the Standard C++ Locales". Rogue Wave Software, Inc..