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/*
FUNCTION
<<mblen>>---minimal multibyte length function
INDEX
mblen
ANSI_SYNOPSIS
#include <stdlib.h>
int mblen(const char *<[s]>, size_t <[n]>);
TRAD_SYNOPSIS
#include <stdlib.h>
int mblen(<[s]>, <[n]>)
const char *<[s]>;
size_t <[n]>;
DESCRIPTION
When MB_CAPABLE is not defined, this is a minimal ANSI-conforming
implementation of <<mblen>>. In this case, the
only ``multi-byte character sequences'' recognized are single bytes,
and thus <<1>> is returned unless <[s]> is the null pointer or
has a length of 0 or is the empty string.
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.
RETURNS
This implementation of <<mblen>> returns <<0>> if
<[s]> is <<NULL>> or the empty string; it returns <<1>> if not MB_CAPABLE or
the character is a single-byte character; it returns <<-1>>
if the multi-byte character is invalid; otherwise it returns
the number of bytes in the multibyte character.
PORTABILITY
<<mblen>> is required in the ANSI C standard. However, the precise
effects vary with the locale.
<<mblen>> requires no supporting OS subroutines.
*/
#ifndef _REENT_ONLY
#include <stdlib.h>
int
_DEFUN (mblen, (s, n),
const char *s _AND
size_t n)
{
#ifdef MB_CAPABLE
_REENT_CHECK_MISC(_REENT);
return _mbtowc_r (_REENT, NULL, s, n, &(_REENT_MBLEN_STATE(_REENT)));
#else /* not MB_CAPABLE */
if (s == NULL || *s == '\0')
return 0;
if (n == 0)
return -1;
return 1;
#endif /* not MB_CAPABLE */
}
#endif /* !_REENT_ONLY */
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