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_snscanf, _snscanf_l, _snwscanf, _snwscanf_l

  • Artikkeli

Reads formatted data of a specified length from a string. More secure versions of these functions are available; see _snscanf_s, _snscanf_s_l, _snwscanf_s, _snwscanf_s_l.

Syntax

int __cdecl _snscanf(
   const char * input,
   size_t length,
   const char * format,
   ...
);
int __cdecl _snscanf_l(
   const char * input,
   size_t length,
   const char * format,
   _locale_t locale,
   ...
);
int __cdecl _snwscanf(
   const wchar_t * input,
   size_t length,
   const wchar_t * format,
   ...
);
int __cdecl _snwscanf_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.

Return value

Both of these functions return the number of fields successfully converted and assigned; the return value doesn't 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.

If input or format is a NULL pointer, or if length is less than or equal to zero, 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 errno, _doserrno, _sys_errlist, and _sys_nerr.

Remarks

This function is like sscanf, except that it lets you specify a fixed number of characters to examine from the input string. For more information, see sscanf.

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 _snscanf _snscanf _snwscanf
_sntscanf_l _snscanf_l _snscanf_l _snwscanf_l

Requirements

Routine Required header
_snscanf, _snscanf_l <stdio.h>
_snwscanf, _snwscanf_l <stdio.h> or <wchar.h>

For more compatibility information, see Compatibility.

Example

// crt_snscanf.c
// compile with: /W3

#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( str1, 6,  "%s %f", s1, &fp); // C4996
   // Note: _snscanf is deprecated; consider using _snscanf_s instead
   printf("_snscanf converted %d fields: ", i);
   printf("%s and %f\n", s1, fp);

   i = _snwscanf( str2, 6,  L"%s %f", s2, &fp); // C4996
   // Note: _snwscanf is deprecated; consider using _snwscanf_s instead
   wprintf(L"_snwscanf converted %d fields: ", i);
   wprintf(L"%s and %f\n", s2, fp);
}

_snscanf converted 2 fields: 15 and 12.000000
_snwscanf converted 2 fields: 15 and 12.000000

See also

scanf Width Specification