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 only known to the mbtowc
function. If s does
not point to a '\0' byte, 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, excepts 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 non-zero if the encoding has non-trivial 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
non-zero if the encoding has non-trivial shift state, or zero
if the encoding is stateless.
The behavior of mbtowc()
depends on the LC_CTYPE
category of the current locale.
This function is not multi-thread safe. The function mbrtowc(3) provides a better interface to the same functionality.
MB_CUR_MAX(3), mbrtowc(3), mbstowcs(3)
|
Copyright (c) Bruno Haible <haibleclisp.cons.org> This is free documentation; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. References consulted: GNU glibc-2 source code and manual Dinkumware C library reference http://www.dinkumware.com/ OpenGroup's Single Unix specification http://www.UNIX-systems.org/online.html ISO/IEC 9899:1999 |