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_scprintf, _scprintf_l, _scwprintf, _scwprintf_l

Returns the number of characters in the formatted string.


int _scprintf(
   const char *format [,
   argument] ...
int _scprintf_l(
   const char *format,
   _locale_t locale [,
   argument] ...
int _scwprintf(
   const wchar_t *format [,
   argument] ...
int _scwprintf_l(
   const wchar_t *format,
   _locale_t locale [,
   argument] ...


Format-control string.

Optional arguments.

The locale to use.

For more information, see Format specification syntax.

Return value

Returns the number of characters that would be generated if the string were to be printed or sent to a file or buffer using the specified formatting codes. The value returned doesn't include the terminating null character. _scwprintf performs the same function for wide characters.

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 -1 and set errno to EINVAL.

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


Each argument (if any) is converted according to the corresponding format specification in format. The format consists of ordinary characters and has the same form and function as the format argument for printf.

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.


Ensure that format is not a user-defined string.

Starting in Windows 10 version 2004 (build 19041), the printf family of functions prints exactly representable floating point numbers according to the IEEE 754 rules for rounding. In previous versions of Windows, exactly representable floating point numbers ending in '5' would always round up. IEEE 754 states that they must round to the closest even digit (also known as "Banker's Rounding"). For example, both printf("%1.0f", 1.5) and printf("%1.0f", 2.5) should round to 2. Previously, 1.5 would round to 2 and 2.5 would round to 3. This change only affects exactly representable numbers. For example, 2.35 (which, when represented in memory, is closer to 2.35000000000000008) continues to round up to 2.4. Rounding done by these functions now also respects the floating point rounding mode set by fesetround. Previously, rounding always chose FE_TONEAREST behavior. This change only affects programs built using Visual Studio 2019 version 16.2 and later. To use the legacy floating point rounding behavior, link with 'legacy_stdio_float_rounding.obj`.

Generic-text routine mappings

Tchar.h routine _UNICODE and _MBCS not defined _MBCS defined _UNICODE defined
_sctprintf _scprintf _scprintf _scwprintf
_sctprintf_l _scprintf_l _scprintf_l _scwprintf_l


Routine Required header
_scprintf, _scprintf_l <stdio.h>
_scwprintf, _scwprintf_l <stdio.h> or <wchar.h>

For more compatibility information, see Compatibility.


// crt__scprintf.c


#include <stdio.h>
#include <math.h>
#include <malloc.h>

int main( void )
   int count;
   int size;
   char *s = NULL;

   count = _scprintf( "The value of Pi is calculated to be %f.\n",

   size = count + 1; // the string will need one more char for the null terminator
   s = malloc(sizeof(char) * size);
   sprintf_s(s, size, "The value of Pi is calculated to be %f.\n",
   printf("The length of the following string will be %i.\n", count);
   printf("%s", s);
   free( s );
The length of the following string will be 46.
The value of Pi is calculated to be 3.141593.

See also

Stream I/O
fprintf, _fprintf_l, fwprintf, _fwprintf_l
printf, _printf_l, wprintf, _wprintf_l
scanf, _scanf_l, wscanf, _wscanf_l
sscanf, _sscanf_l, swscanf, _swscanf_l
vprintf functions