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.
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.
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