mbtowc [minimal multibyte to wide char converter]

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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.