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MBRLEN(3) FreeBSD Library Functions Manual MBRLEN(3)
NAME
mbrlen - get number of bytes in a character (restartable)
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <wchar.h>
size_t
mbrlen(const char * restrict s, size_t n, mbstate_t * restrict ps);
DESCRIPTION
The mbrlen() function inspects at most n bytes pointed to by s to
determine the number of bytes needed to complete the next multibyte
character.
The mbstate_t argument, ps, is used to keep track of the shift state. If
it is NULL, mbrlen() uses an internal, static mbstate_t object, which is
initialized to the initial conversion state at program startup.
It is equivalent to:
mbrtowc(NULL, s, n, ps);
Except that when ps is a NULL pointer, mbrlen() uses its own static,
internal mbstate_t object to keep track of the shift state.
RETURN VALUES
The mbrlen() functions returns:
0 The next n or fewer bytes represent the null wide character
(L'\0').
>0 The next n or fewer bytes represent a valid character, mbrlen()
returns the number of bytes used to complete the multibyte
character.
(size_t)-2
The next n contribute to, but do not complete, a valid multibyte
character sequence, and all n bytes have been processed.
(size_t)-1
An encoding error has occurred. The next n or fewer bytes do not
contribute to a valid multibyte character.
EXAMPLES
A function that calculates the number of characters in a multibyte
character string:
size_t
nchars(const char *s)
{
size_t charlen, chars;
mbstate_t mbs;
chars = 0;
return (chars);
}
ERRORS
The mbrlen() function will fail if:
[EILSEQ] An invalid multibyte sequence was detected.
[EINVAL] The conversion state is invalid.
SEE ALSO
mblen(3), mbrtowc(3), multibyte(3)
STANDARDS
The mbrlen() function conforms to ISO/IEC 9899:1999 ("ISO C99").
FreeBSD 14.0-RELEASE-p11 April 7, 2004 FreeBSD 14.0-RELEASE-p11