mblen.3int

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" This file contains the ditroff text for the mblen() function.
.TH mblen 3int
.SH Name
mblen \- determines the number of bytes comprising a multibyte character
.SH Syntax
#include <stdlib.h>
.PP
int mblen\fI (s, n)\fR
.br
const char\fI *s;\fR
.br
size_t\fI n; \fR
.SH Arguments
.TP 8
.I s
The 
.I s
argument is a pointer to the multibyte character string.
.PP
.TP 8 
.I n
The 
.I n 
argument is the maximum number of bytes in 
.I s
that are examined. 
.SH Description
.NXR "multibyte character length function"
If \fIs\fR is not a null pointer, the 
.PN mblen
function determines
the number of bytes comprising the multibyte character
pointed to by \fIs\fR.
The 
.PN mblen 
function is equivalent to:
.EX 
\fI(mbtowc((wchar_t *)0, s, n);)\fR
.EE
.PP
This function is affected by the LC_CTYPE category of the
current locale.
.SH Return Values
If \fIs\fR is a null pointer, the 
.PN mblen 
function returns a zero value.
If \fIs\fR is not a null pointer, the 
.PN mblen 
function returns:
.RS 3
.IP \(bu 3
0 (if \fIs\fR points to the null character)
.IP \(bu 3
The number
of bytes that comprise the multibyte character (if the next
\fIn\fR or fewer bytes form a valid multibyte character)
.IP \(bu 3
 -1 (if they do not form a valid multibyte character)
.RE
.SH See Also
mbtowc(3int), mbstowcs(3int), setlocale(3int), wctomb(3int),
wcstombs(3int)