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/*
FUNCTION
<<mbstowcs>>---minimal multibyte string to wide char converter
INDEX
mbstowcs
ANSI_SYNOPSIS
#include <stdlib.h>
int mbstowcs(wchar_t *<[pwc]>, const char *<[s]>, size_t <[n]>);
TRAD_SYNOPSIS
#include <stdlib.h>
int mbstowcs(<[pwc]>, <[s]>, <[n]>)
wchar_t *<[pwc]>;
const char *<[s]>;
size_t <[n]>;
DESCRIPTION
When MB_CAPABLE is not defined, this is a minimal ANSI-conforming
implementation of <<mbstowcs>>. In this case, the
only ``multi-byte character sequences'' recognized are single bytes,
and they are ``converted'' to wide-char versions simply by byte
extension.
When MB_CAPABLE is defined, this routine calls <<_mbstowcs_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.
RETURNS
This implementation of <<mbstowcs>> returns <<0>> if
<[s]> is <<NULL>> or is the empty string;
it returns <<-1>> if MB_CAPABLE and one of the
multi-byte characters is invalid or incomplete;
otherwise it returns the minimum of: <<n>> or the
number of multi-byte characters in <<s>> plus 1 (to
compensate for the nul character).
If the return value is -1, the state of the <<pwc>> string is
indeterminate. If the input has a length of 0, the output
string will be modified to contain a wchar_t nul terminator.
PORTABILITY
<<mbstowcs>> is required in the ANSI C standard. However, the precise
effects vary with the locale.
<<mbstowcs>> requires no supporting OS subroutines.
*/
#ifndef _REENT_ONLY
#include <stdlib.h>
#include <wchar.h>
size_t
_DEFUN (mbstowcs, (pwcs, s, n),
wchar_t *pwcs _AND
const char *s _AND
size_t n)
{
#ifdef MB_CAPABLE
mbstate_t state;
state.__count = 0;
return _mbstowcs_r (_REENT, pwcs, s, n, &state);
#else /* not MB_CAPABLE */
int count = 0;
if (n != 0) {
do {
if ((*pwcs++ = (wchar_t) *s++) == 0)
break;
count++;
} while (--n != 0);
}
return count;
#endif /* not MB_CAPABLE */
}
#endif /* !_REENT_ONLY */
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