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_vcprintf_s, _vcprintf_s_l, _vcwprintf_s, _vcwprintf_s_l

Write formatted output to the console using a pointer to a list of arguments. These are versions of _vcprintf, _vcprintf_l, _vcwprintf, _vcwprintf_l with security enhancements as described in Security Features in the CRT.

Important note Important

This API cannot be used in applications that execute in the Windows Runtime. For more information, see CRT functions not supported with /ZW.

int _vcprintf(
   const char* format,
   va_list argptr
int _vcprintf(
   const char* format,
   locale_t locale,
   va_list argptr
int _vcwprintf_s(
   const wchar_t* format,
   va_list argptr
int _vcwprintf_s_l(
   const wchar_t* format,
   locale_t locale,
   va_list argptr


Format specification.


Pointer to list of arguments.


The locale to use.

For more information, see Format Specifications.

The number of characters written, or a negative value if an output error occurs.

Like the non-secure version of these functions, if format is a null pointer, the invalid parameter handler is invoked, as described in Parameter Validation. Additionally, unlike the non-secure version of these functions, if format does not specify a valid format, an invalid parameter exception is generated. If execution is allowed to continue, these functions return

Each of these functions takes a pointer to an argument list, then formats and writes the given data to the console. _vcwprintf_s is the wide-character version of _vcprintf_s. It takes a wide-character string as an argument.

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.

Security note Security Note

Ensure that format is not a user-defined string. For more information, see Avoiding Buffer Overruns.

Generic-Text Routine Mappings

TCHAR.H routine

_UNICODE & _MBCS not defined

_MBCS defined

_UNICODE defined










Required header

Optional headers

_vcprintf_s , _vcprintf_s_l

<conio.h> and <stdarg.h>


_vcwprintf_s , _vcwprintf_s_l

<conio.h> or <wchar.h>, and <stdarg.h>


* Required for UNIX V compatibility.

For additional compatibility information, see Compatibility in the Introduction.

// crt_vcprintf_s.cpp
#include <conio.h>
#include <stdarg.h>

// An error formatting function used to print to the console.
int eprintf_s(const char* format, ...)
  va_list args;
  va_start(args, format);
  return _vcprintf_s(format, args);

int main()
   eprintf_s("  (%d:%d): Error %s%d : %s\n", 10, 23, "C", 2111,
           "<some error text>");
   eprintf_s("  (Related to symbol '%s' defined on line %d).\n",
           "<symbol>", 5 );
(10,23): Error C2111 : <some error text>
  (Related to symbol '<symbol>' defined on line 5).
© 2015 Microsoft