mbtowc
[minimal multibyte to wide
char converter]
SYNOPSIS
#include<stdlib.h>
int mbtowc(wchar_t *pwc,
const char *s, size_t n);
DESCRIPTION
When MB_CAPABLE
is not defined, this is a minimal ANSI-conforming implementation of mbtowc.
In this case, only multibyte character sequences recognized are
single bytes, and they are converted to themselves. Each call to
mbtowc copies one character from *s
to *pwc,
unless s
is a null pointer. The argument, n,
is ignored.
When MB_CAPABLE is defined, this routine calls _mbtowc_r to perform the conversion, passing a state variable to allow state dependent decoding. The result is based on the locale setting which may be restricted to a defined set of locales.The only multibyte character sequences recognized are single bytes, and they are converted to themselves.
RETURNS
This implementation of mbtowc
returns 0 if s
is NULL or is the empty string; it returns 1
if not MB_CAPABLE
or the character is a single-byte character; it returns -1
if n
is 0 or the multibyte character is invalid; otherwise, it returns the number
of bytes in the multibyte character. If the return value is -1,
no changes are made to the pwc
output string. If the input is the empty string, a wchar_t
nul is placed in the output string
and 0 is returned. If the input has a length of 0,
no changes are made to the pwc
output string.
COMPLIANCE
mbtowc is required
in the ANSI C standard. However, the precise effects vary with the locale.
mbtowc requires no supporting OS subroutines.