scanf()

/***
*scanf.c - read formatted data from stdin
*
* Copyright (c) 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 vscanf_fn(format, ...) - read formatted data from stdin
*
*Purpose:
* This is a helper function to be called from fscanf & fscanf_s
*
*Entry:
* INPUTFN inputfn - scanf & scanf_s pass either _input_l or _input_s_l
* which is then used to do the real work.
* char *format - format string
* va_list arglist - arglist of output pointers
*
*Exit:
* returns number of fields read and assigned
*
*Exceptions:
*
*******************************************************************************/

int __cdecl vscanf_fn (
INPUTFN inputfn,
const char *format,
_locale_t plocinfo,
va_list arglist
)
/*
* stdin ‘SCAN‘, ‘F‘ormatted
*/
{
int retval = 0;

_VALIDATE_RETURN( (format != NULL), EINVAL, EOF);

_lock_str2(0, stdin);
__try {
retval = (inputfn(stdin, format, plocinfo, arglist));
}
__finally {
_unlock_str2(0, stdin);
}

return(retval);
}

/***
*int scanf(format, ...) - read formatted data from stdin
*
*Purpose:
* Reads formatted data from stdin into arguments. _input_l 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,
...
)
{
va_list arglist;
va_start(arglist, format);
return vscanf_fn(_input_l, format, NULL, arglist);
}

int __cdecl vscanf (
const char *format,
va_list arglist
)
{
return vscanf_fn(_input_l, format, NULL, arglist);
}

int __cdecl _scanf_l (
const char *format,
_locale_t plocinfo,
...
)
{
va_list arglist;
va_start(arglist, plocinfo);
return vscanf_fn(_input_l, format, plocinfo, arglist);
}

/***
*int scanf_s(format, ...) - read formatted data from stdin
*
* Same as scanf above except that it calls _input_s_l to do the real work.
* _input_s_l has a size check for array parameters.
*
*******************************************************************************/
int __cdecl scanf_s (
const char *format,
...
)
{
va_list arglist;
va_start(arglist, format);
return vscanf_fn(_input_s_l, format, NULL, arglist);
}

int __cdecl vscanf_s (
const char *format,
va_list arglist
)
{
return vscanf_fn(_input_s_l, format, NULL, arglist);
}

int __cdecl _scanf_s_l (
const char *format,
_locale_t plocinfo,
...
)
{
va_list arglist;
va_start(arglist, plocinfo);
return vscanf_fn(_input_s_l, format, plocinfo, arglist);
}

scanf()

原文：https://www.cnblogs.com/tianqiang/p/9350921.html