scanf, _scanf_l, wscanf, _wscanf_l

 

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Reads formatted data from the standard input stream. More secure versions of these function are available; see scanf_s, _scanf_s_l, wscanf_s, _wscanf_s_l.

int scanf(  
   const char *format [,  
   argument]...   
);  
int _scanf_l(  
   const char *format,  
   locale_t locale [,  
   argument]...   
);  
int wscanf(  
   const wchar_t *format [,  
   argument]...   
);  
int _wscanf_l(  
   const wchar_t *format,  
   locale_t locale [,  
   argument]...   
);  

Parameters

format
Format control string.

argument
Optional arguments.

locale
The locale to use.

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.

If 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 on these and other error codes, see _doserrno, errno, _sys_errlist, and _sys_nerr.

The scanf function reads data from the standard input stream stdin and writes the data into the location given by argument. Each argument must be a pointer to a variable of a type that corresponds to a type specifier in format. If copying takes place between strings that overlap, the behavior is undefined.

System_CAPS_ICON_important.jpg Important

When reading a string with scanf, always specify a width for the %s format (for example, "%32s" instead of "%s"); otherwise, improperly formatted input can easily cause a buffer overrun. Alternately, consider using scanf_s, _scanf_s_l, wscanf_s, _wscanf_s_l or fgets.

wscanf is a wide-character version of scanf; the format argument to wscanf is a wide-character string. wscanf and scanf behave identically if the stream is opened in ANSI mode. scanf doesn't currently support input from a UNICODE stream.

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 & _MBCS not defined_MBCS defined_UNICODE defined
_tscanfscanfscanfwscanf
_tscanf_l_scanf_l_scanf_l_wscanf_l

For more information, see Format Specification Fields — scanf functions and wscanf Functions.

RoutineRequired header
scanf, _scanf_l<stdio.h>
wscanf, _wscanf_l<stdio.h> or <wchar.h>

The console is not supported in Windows 8.x Store apps. The standard stream handles that are associated with the console—stdin, stdout, and stderr—must be redirected before C run-time functions can use them in Windows 8.x Store apps. For additional compatibility information, see Compatibility.

// crt_scanf.c  
// compile with: /W3  
 /* This program uses the scanf and wscanf functions  
  * to read formatted input.  
  */  
  
#include <stdio.h>  
  
int main( void )  
{  
   int   i, result;  
   float fp;  
   char  c, s[81];  
   wchar_t wc, ws[81];  
   result = scanf( "%d %f %c %C %80s %80S", &i, &fp, &c, &wc, s, ws ); // C4996  
   // Note: scanf and wscanf are deprecated; consider using scanf_s and wscanf_s  
   printf( "The number of fields input is %d\n", result );  
   printf( "The contents are: %d %f %c %C %s %S\n", i, fp, c, wc, s, ws);  
   result = wscanf( L"%d %f %hc %lc %80S %80ls", &i, &fp, &c, &wc, s, ws ); // C4996  
   wprintf( L"The number of fields input is %d\n", result );  
   wprintf( L"The contents are: %d %f %C %c %hs %s\n", i, fp, c, wc, s, ws);  
}  

  
      71 98.6 h z Byte characters  
36 92.3 y n Wide charactersThe number of fields input is 6  
The contents are: 71 98.599998 h z Byte characters  
The number of fields input is 6  
The contents are: 36 92.300003 y n Wide characters  

Floating-Point Support
Stream I/O
Locale
fscanf, _fscanf_l, fwscanf, _fwscanf_l
printf, _printf_l, wprintf, _wprintf_l
sprintf, _sprintf_l, swprintf, _swprintf_l, __swprintf_l
sscanf, _sscanf_l, swscanf, _swscanf_l

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