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_cprintf_s, _cprintf_s_l, _cwprintf_s, _cwprintf_s_l

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Formats and prints to the console. These versions of _cprintf, _cprintf_l, _cwprintf, _cwprintf_l have security enhancements, as described in Security features in the CRT.

Important

This API cannot be used in applications that execute in the Windows Runtime. For more information, see CRT functions not supported in Universal Windows Platform apps.

Syntax

int _cprintf_s(
   const char * format [,
   argument] ...
);
int _cprintf_s_l(
   const char * format,
   _locale_t locale [,
   argument] ...
);
int _cwprintf_s(
   const wchar * format [,
   argument] ...
);
int _cwprintf_s_l(
   const wchar * format,
   _locale_t locale [,
   argument] ...
);

Parameters

format
Format-control string.

argument
Optional parameters.

locale
The locale to use.

Return value

The number of characters printed.

Remarks

These functions format and print a series of characters and values directly to the console, using the _putch function (_putwch for _cwprintf_s) to output characters. Each argument (if any) is converted and output according to the corresponding format specification in format. The format has the same form and function as the format parameter for the printf_s function. Unlike the fprintf_s, printf_s, and sprintf_s functions, _cprintf_s and _cwprintf_s don't translate line-feed characters into carriage return-line feed (CR-LF) combinations when output.

An important distinction is that _cwprintf_s displays Unicode characters when used in Windows NT. Unlike _cprintf_s, _cwprintf_s uses the current console locale

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

Important

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`.

Like the non-secure versions (see _cprintf, _cprintf_l, _cwprintf, _cwprintf_l), these functions validate their parameters and invoke the invalid parameter handler, as described in Parameter validation, if format is a null pointer. These functions differ from the non-secure versions in that the format string itself is also validated. If there are any unknown or badly formed formatting specifiers, these functions invoke the invalid parameter handler. In all cases, If execution is allowed to continue, the functions return -1 and set errno to EINVAL.

Generic-text routine mappings

Tchar.h routine _UNICODE and _MBCS not defined _MBCS defined _UNICODE defined
_tcprintf_s _cprintf_s _cprintf_s _cwprintf_s
_tcprintf_s_l _cprintf_s_l _cprintf_s_l _cwprintf_s_l

Requirements

Routine Required header
_cprintf_s, _cprintf_s_l <conio.h>
_cwprintf_s, _cwprintf_s_l <conio.h>

For more compatibility information, see Compatibility.

Libraries

All versions of the C run-time libraries.

Example

// crt_cprintf_s.c
// compile with: /c
// This program displays some variables to the console.

#include <conio.h>

int main( void )
{
   int      i = -16, h = 29;
   unsigned u = 62511;
   char     c = 'A';
   char     s[] = "Test";

   /* Note that console output does not translate \n as
    * standard output does. Use \r\n instead.
    */
   _cprintf_s( "%d  %.4x  %u  %c %s\r\n", i, h, u, c, s );
}

-16  001d  62511  A Test

See also

Console and port I/O
_cscanf, _cscanf_l, _cwscanf, _cwscanf_l
fprintf_s, _fprintf_s_l, fwprintf_s, _fwprintf_s_l
printf_s, _printf_s_l, wprintf_s, _wprintf_s_l
sprintf_s, _sprintf_s_l, swprintf_s, _swprintf_s_l
vfprintf_s, _vfprintf_s_l, vfwprintf_s, _vfwprintf_s_l
Format specification syntax: printf and wprintf functions