mbtowc.3int

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 3INT 代码 · 共 82 行

.TH mbtowc 3int
.SH Name
mbtowc \- converts a single multibyte character into a 
character of type wchar_t
.SH Syntax
#include <stdlib.h>
.PP
int mbtowc \fI(pwc, s, n)\fR
.br
wchar_t \fI*pwc;\fR
.br
const char \fI*s;\fR
.br
size_t\fI n;\fR
.SH Arguments
.TP 8
.I pwc
The 
.I pwc
argument is a pointer to the resulting object of type 
wchar_t.
.PP
.TP 8
.I s
The
.I s
argument is a pointer to a multibyte character.
.PP
.TP 8
.I n
The 
.I n 
argument is the maximum number of bytes of object 
.I s
that are examined. 
.SH Description
.NXR "multibyte character to wide character conversion function"
If \fIs\fR is not a null pointer,
the 
.PN mbtowc
function determines the number of
bytes that comprise the multibyte character pointed to by \fIs\fR.
It then determines the character code for the value (of type 
wchar_t) that
corresponds to that multibyte character (the value of the code
corresponding to the null character is zero). If the multibyte character 
is valid and \fIpwc\fR is not a null pointer,
the 
.PN mbtowc
function stores
the code in the object pointed to by \fIpwc\fR.  At most
\fIn\fR bytes of the 
array pointed to by \fIs\fR are examined.
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 mbtowc
function returns a zero value.
If \fIs\fR is not a null pointer,
the 
.PN mbtowc
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 converted multibye character, if the next \fIn\fR
or fewer bytes form a valid multibye character
.IP \(bu 3 
- -1, if the next \fIn\fR or fewer bytes do not form a valid 
multibye character
.RE
.PP
In no case is the value returned greater than \fIn\fR or the
value of the MB_CUR_MAX macro.
.SH See Also
mblen(3int), mbstowcs(3int), setlocale(3int), wctomb(3int), 
wcstombs(3int)