scanf的实现源码

/***

*scanf.c - read formatted data from stdin

*

*       Copyright (c) 1985-1997, Microsoft Corporation. All rights reserved.

*

*Purpose:

*       defines scanf() - reads formatted data from stdin

*

*******************************************************************************/



#include <cruntime.h>

#include <stdio.h>

#include <dbgint.h>

#include <stdarg.h>

#include <file2.h>

#include <internal.h>

#include <mtdll.h>



/***

*int scanf(format, ...) - read formatted data from stdin

*

*Purpose:

*       Reads formatted data from stdin into arguments.  _input does the real

*       work here.

*

*Entry:

*       char *format - format string

*       followed by list of pointers to storage for the data read.  The number

*       and type are controlled by the format string.

*

*Exit:

*       returns number of fields read and assigned

*

*Exceptions:

*

*******************************************************************************/



int __cdecl scanf (

        const char *format,

        ...

        )

/*

 * stdin 'SCAN', 'F'ormatted

 */

{

        int retval;



        va_list arglist;



        va_start(arglist, format);



        _ASSERTE(format != NULL);



        _lock_str2(0, stdin);



        retval = (_input(stdin,format,arglist));



        _unlock_str2(0, stdin);



        return(retval);

}