snprintf.gml

来自「开放源码的编译器open watcom 1.6.0版的源代码」· GML 代码 · 共 98 行

.func snprintf snwprintf
.funcw snwprintf
#include <stdio.h>
int snprintf( char *buf,
              size_t count,
              const char *format, ... );
.ixfunc2 '&String' &func
.if &'length(&wfunc.) ne 0 .do begin
#include <wchar.h>
int snwprintf( wchar_t *buf,
               size_t count,
               const wchar_t *format, ... );
.ixfunc2 '&String' &wfunc
.ixfunc2 '&Wide &wfunc
.do end
.funcend
.*
.safealt
.*
.desc begin
The &func function is equivalent to the
.kw fprintf
function, except that the argument
.arg buf
specifies a character array into which the generated output is placed,
rather than to a file.
A null character is placed at the end of the generated character
string.
The maximum number of characters to store, including a terminating
null character, is specified by
.arg count.
The
.arg format
string is described under the description of the
.kw printf
function.
.if &'length(&wfunc.) ne 0 .do begin
.np
The &wfunc function is identical to &func except that the argument
.arg buf
specifies an array of wide characters into which the generated output
is to be written, rather than converted to multibyte characters and
written to a stream.
The maximum number of wide characters to store, including a
terminating null wide character, is specified by
.arg count.
The &wfunc function accepts a wide-character string argument for
.arg format
.do end
.desc end
.*
.return begin
The &func function returns the number of characters that would have been
written had
.arg count
been sufficiently large, not counting the terminating null
character, or a negative value if an encoding error occurred.
Thus, the null-terminated output has been completely written if and only
if the returned value is nonnegative and less than
.arg count.
.if &'length(&wfunc.) ne 0 .do begin
The &wfunc function returns the number of wide characters that would have
been written had
.arg count
been sufficiently large, not counting the terminating null wide character,
or a negative value if an encoding error occurred.
Thus, the null-terminated output has been completely written if and only
if the returned value is nonnegative and less than
.arg count.
.do end
.im errnoref
.return end
.*
.see begin
.im seeprtf snprintf
.see end
.*
.exmp begin
#include <stdio.h>
#include <stdlib.h>

/* Format output into a buffer after determining its size */

void main( void )
{
    int     bufsize;
    char    *buffer;

    bufsize = snprintf( NULL, 0, "%3d %P", 42, 42 );
    buffer  = malloc( bufsize + 1 );
    snprintf( buffer, bufsize + 1, "%3d %P", 42, 42 );
    free( buffer );
}
.exmp end
.*
.class ANSI
.system