wcstombs - convert a wide-character string to a multibyte string
Standard C library (
libc,
-lc)
#include <stdlib.h>
size_t wcstombs(char dest[restrict .n], const wchar_t *restrict src,
size_t n);
If
dest is not NULL, 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 sequence
of characters placed in
dest begins in the initial shift state. The
conversion can stop for three reasons:
- •
- 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.
- •
- 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.
- •
- The wide-character string has been completely converted,
including the terminating null wide character (L'\0'). In this case, the
conversion ends in the initial shift state. The number of bytes written to
dest, excluding the terminating null byte ('\0'), 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 converted bytes are not written out to memory, and no
length limit exists.
In order to avoid the case 2 above, the programmer should make sure
n is
greater than or equal to
wcstombs(NULL,src,0)+1.
The
wcstombs() function returns the number of bytes that make up the
converted part of a multibyte sequence, not including the terminating null
byte. If a wide character was encountered which could not be converted,
(size_t) -1 is returned.
For an explanation of the terms used in this section, see
attributes(7).
Interface |
Attribute |
Value |
wcstombs () |
Thread safety |
MT-Safe |
POSIX.1-2001, POSIX.1-2008, C99.
The behavior of
wcstombs() depends on the
LC_CTYPE category of the
current locale.
The function
wcsrtombs(3) provides a better interface to the same
functionality.
mblen(3),
mbstowcs(3),
mbtowc(3),
wcsrtombs(3),
wctomb(3)