WCRTOMB(3)

NAME
wcrtomb, wcrtomb_l - convert a wide character to a multibyte character (restartable)

SYNOPSIS
#include <wchar.h>
size_t
wcrtomb(const char * restrict s, wchar_t wc, mbstate_t * restrict ps);
#include <xlocale.h>
size_t
wcrtomb_l(const char * restrict s, wchar_t wc, mbstate_t * restrict ps, locale_t loc);

DESCRIPTION
wcrtomb() and wcrtomb_l() convert the wide character given by wc to the corresponding multibyte character, and store up to MB_CUR_MAX bytes in the array pointed to by s if s is not a null pointer.

The behaviour of wcrtomb() is affected by the LC_CTYPE category of the current locale, while wcrtomb_l() uses the locale given as parameter.

These are the special cases:

wc == 0
    For state-dependent encodings, wcrtomb() stores a null byte preceded by a special byte sequence (if any) to return to an initial state to the array pointed by s, and the state object pointed by ps also returned to an initial state.

s == NULL
    wcrtomb() just places ps into an initial state. It is equivalent to the following call:

        wcrtomb(buf, L'\0', ps);

    Here, buf is a dummy buffer. In this case, wc is ignored.

ps == NULL
    mbrtowc() uses its own internal state object to keep the conversion state, instead of ps mentioned in this manual page.

    Calling any other functions in libc never change the internal state of mbrtowc(), which is initialized at startup time of the program.

RETURN VALUES
wcrtomb() returns the number of bytes (including any shift sequences) which are stored in the array pointed to by s. If wc is not a valid wide character, wcrtomb() returns (size_t)-1 and sets errno to indicate error.

ERRORS
wcrtomb() may cause an error in the following cases:

[EILSEQ]
    wc is not a valid wide character.

[EINVAL]
    ps points to an invalid or uninitialized mbstate_t object.

SEE ALSO
setlocale(3), wctomb(3), xlocale(3)

STANDARDS
The wcrtomb() function conforms to ISO/IEC 9899/AMD1:1995 (“ISO C90, Amendment 1”). The restrict qualifier is added at ISO/IEC 9899/1999 (“ISO C99”). The wcrtomb_l() function is a Darwin extension.