WCSTOMBS(3) Linux Programmer's Manual WCSTOMBS(3)
wcstombs - convert a wide character string to a multibyte string
size_t wcstombs(char *dest, const wchar_t *src, size_t n);
If dest is not a NULL pointer, the wcstombs function converts the wide-character string
src to a multibyte string starting at dest. At most n bytes are written to dest. The con-
version starts in the initial state. The conversion can stop for three reasons:
1. A wide character has been encountered that can not be represented as a multibyte
sequence (according to the current locale). In this case (size_t)(-1) is returned.
2. The length limit forces a stop. In this case the number of bytes written to dest is
returned, but the shift state at this point is lost.
3. The wide-character string has been completely converted, including the terminating
L'\0'. In this case the conversion ends in the initial state. The number of bytes written
to dest, excluding the terminating '\0' byte, is returned.
The programmer must ensure that there is room for at least n bytes at dest.
If dest is NULL, n is ignored, and the conversion proceeds as above, except that the con-
verted bytes are not written out to memory, and that no length limit exists.
In order to avoid the case 2 above, the programmer should make sure n is greater or equal
The wcstombs function returns the number of bytes that make up the converted part of
multibyte sequence, not including the terminating null byte. If a wide character was
encountered which could not be converted, (size_t)(-1) is returned.
ISO/ANSI C, UNIX98
The behaviour of wcstombs depends on the LC_CTYPE category of the current locale.
The function wcsrtombs provides a thread safe interface to the same functionality.
GNU 1999-07-25 WCSTOMBS(3)