mbtowc - convert a multibyte sequence to a wide character
#include <stdlib.h>
int mbtowc(wchar_t *pwc, const char *s, size_t n);
The main case for this function is when
s is not NULL and
pwc is
not NULL. In this case, the
mbtowc() function inspects at most
n
bytes of the multibyte string starting at
s, extracts the next complete
multibyte character, converts it to a wide character and stores it at
*pwc. It updates an internal shift state known only to the
mbtowc() function. If
s does not point to a null byte ('\0'), it
returns the number of bytes that were consumed from
s, otherwise it
returns 0.
If the
n bytes starting at
s do not contain a complete multibyte
character, or if they contain an invalid multibyte sequence,
mbtowc()
returns -1. This can happen even if
n >=
MB_CUR_MAX, if the
multibyte string contains redundant shift sequences.
A different case is when
s is not NULL but
pwc is NULL. In this
case, the
mbtowc() function behaves as above, except that it does not
store the converted wide character in memory.
A third case is when
s is NULL. In this case,
pwc and
n are
ignored. The
mbtowc() function resets the shift state, only known to
this function, to the initial state, and returns nonzero if the encoding has
nontrivial shift state, or zero if the encoding is stateless.
If
s is not NULL, the
mbtowc() function returns the number of
consumed bytes starting at
s, or 0 if
s points to a null byte,
or -1 upon failure.
If
s is NULL, the
mbtowc() function returns nonzero if the
encoding has nontrivial shift state, or zero if the encoding is stateless.
For an explanation of the terms used in this section, see
attributes(7).
| Interface |
Attribute |
Value |
| mbtowc () |
Thread safety |
MT-Unsafe race |
POSIX.1-2001, POSIX.1-2008, C99.
The behavior of
mbtowc() depends on the
LC_CTYPE category of the
current locale.
This function is not multithread safe. The function
mbrtowc(3) provides a
better interface to the same functionality.
MB_CUR_MAX(3),
mblen(3),
mbrtowc(3),
mbstowcs(3),
wcstombs(3),
wctomb(3)