vfprintf.c

C标准库源代码

/***
*vfprintf.c - fprintf from variable arg list
*
*       Copyright (c) 1985-1997, Microsoft Corporation. All rights reserved.
*
*Purpose:
*       defines vfprintf() - print formatted output, but take args from
*       a stdargs pointer.
*
*******************************************************************************/

#include <cruntime.h>
#include <stdio.h>
#include <dbgint.h>
#include <stdarg.h>
#include <file2.h>
#include <internal.h>
#include <mtdll.h>

/***
*int vfprintf(stream, format, ap) - print to file from varargs
*
*Purpose:
*       Performs formatted output to a file.  The arg list is a variable
*       argument list pointer.
*
*Entry:
*       FILE *stream - stream to write data to
*       char *format - format string containing data format
*       va_list ap - variable arg list pointer
*
*Exit:
*       returns number of correctly output characters
*       returns negative number if error occurred
*
*Exceptions:
*
*******************************************************************************/

int __cdecl vfprintf (
        FILE *str,
        const char *format,
        va_list ap
        )
/*
 * 'V'ariable argument 'F'ile (stream) 'PRINT', 'F'ormatted
 */
{
        REG1 FILE *stream;
        REG2 int buffing;
        REG3 int retval;

        _ASSERTE(str != NULL);
        _ASSERTE(format != NULL);

        /* Init stream pointer */
        stream = str;

        _lock_str(stream);
        buffing = _stbuf(stream);
        retval = _output(stream,format,ap );
        _ftbuf(buffing, stream);
        _unlock_str(stream);

        return(retval);
}