converts a wide character to a
multibyte character (restartable)
char * restrict s,
mbstate_t * restrict
converts the wide character given by wc to the
corresponding multibyte character, and stores up to
MB_CUR_MAX bytes in the array pointed to by
s if s is not a null
The behaviour of
is affected by the
LC_CTYPE category of the current
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.
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
wcrtomb() returns (size_t)-1 and sets
errno to indicate error.
wcrtomb() may cause an error in the
- wc is not a valid wide character.
- ps points to an invalid or uninitialized mbstate_t object.
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”).