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_snscanf_s, _snscanf_s_l, _snwscanf_s, _snwscanf_s_l 

Reads formatted data of a specified length from a string. These are versions of _snscanf, _snscanf_l, _snwscanf, _snwscanf_l with security enhancements as described in Security Enhancements in the CRT.


int __cdecl _snscanf_s(
   const char * input,
   size_t length,
   const char * format,
   ...
);
int __cdecl _snscanf_s_l(
   const char * input,
   size_t length,
   const char * format,
   locale_t locale,
   ...
);
int __cdecl _snwscanf_s(
   const wchar_t * input,
   size_t length,
   const wchar_t * format,
   ...
);
int __cdecl _snwscanf_s_l(
   const wchar_t * input,
   size_t length,
   const wchar_t * format,
   locale_t locale,
   …
);

Parameters

input

Input string to examine.

length

Number of characters to examine in input.

format

One or more format specifiers.

... (optional)

Variables that will be used to store the values extracted from the input string by the format specifiers in format.

locale

The locale to use.

Both of these functions returns the number of fields successfully converted and assigned; the return value does not include fields that were read but not assigned. A return value of 0 indicates that no fields were assigned. The return value is EOF for an error or if the end of the string is reached before the first conversion. For more information, see sscanf_s, _sscanf_s_l, swscanf_s, _swscanf_s_l.

If input or format is a NULL pointer, the invalid parameter handler is invoked, as described in Parameter Validation. If execution is allowed to continue, these functions return EOF and set errno to EINVAL.

For information about these and other error codes, see _doserrno, errno, _sys_errlist, and _sys_nerr.

This function is like sscanf_s except that it provides the ability to specify a fixed number of characters to examine from the input string. For more information, see sscanf_s, _sscanf_s_l, swscanf_s, _swscanf_s_l.

The buffer size parameter is required with the type field characters c, C, s, S, and [. For more information, see scanf Type Field Characters.

NoteNote

The size parameter is of type unsigned, not size_t.

The versions of these functions with the _l suffix are identical except that they use the locale parameter passed in instead of the current thread locale.

Generic-Text Routine Mappings
Tchar.h routine _UNICODE and _MBCS not defined _MBCS defined _UNICODE defined

_sntscanf_s

_snscanf_s

_snscanf_s

_snwscanf_s

_sntscanf_s_l

_snscanf_s_l

_snscanf_s_l

_snwscanf_s_l

Routine Required header Compatibility

_snscanf_s, _snscanf_s_l

<stdio.h>

Windows 95, Windows 98, Windows 98 Second Edition, Windows Millennium Edition, Windows NT 4.0, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003

_snwscanf_s, _snwscanf_s_l

<stdio.h> or <wchar.h>

Windows 95, Windows 98, Windows 98 Second Edition, Windows Millennium Edition, Windows NT 4.0, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003

For more compatibility information, see Compatibility in the Introduction.

// crt_snscanf_s.c
// This example scans a string of 
// numbers, using both the character
// and wide character secure versions
// of the snscanf function.

#include <stdio.h>

int main( )
{
    char        str1[] = "15 12 14...";
    wchar_t     str2[] = L"15 12 14...";
    char        s1[3];
    wchar_t     s2[3];
    int         i;
    float       fp;

    i = _snscanf_s( str1, 6,  "%s %f", s1, 3, &fp);
    printf_s("_snscanf_s converted %d fields: ", i);
    printf_s("%s and %f\n", s1, fp);

    i = _snwscanf_s( str2, 6,  L"%s %f", s2, 3, &fp);
    wprintf_s(L"_snwscanf_s converted %d fields: ", i);
    wprintf_s(L"%s and %f\n", s2, fp);
}

Output

_snscanf_s converted 2 fields: 15 and 12.000000
_snwscanf_s converted 2 fields: 15 and 12.000000

Not applicable. To call the standard C function, use PInvoke. For more information, see Platform Invoke Examples.

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