_vcprintf_s, _vcprintf_s_l, _vcwprintf_s, _vcwprintf_s_l

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


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.


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 the list of arguments.

The locale to use.

For more information, see Format Specification Syntax: printf and wprintf Functions.

Return Value

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

Like the less secure versions of these functions, if format is a null pointer, the invalid parameter handler is invoked, as described in Parameter Validation. Additionally, unlike the less secure versions 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 an error code and set errno to that error code. The default error code is EINVAL if a more specific value does not apply.


Each of these functions takes a pointer to an argument list, and 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 that have the _l suffix are identical except that they use the locale parameter that's passed in instead of the current locale.


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
_vtcprintf_s _vcprintf_s _vcprintf_s _vcwprintf_s
_vtcprintf_s_l _vcprintf_s_l _vcprintf_s_l _vcwprintf_s_l


Routine Required header Optional headers
_vcprintf_s, _vcprintf_s_l <conio.h> and <stdarg.h> <varargs.h>*
_vcwprintf_s, _vcwprintf_s_l <conio.h> or <wchar.h>, and <stdarg.h> <varargs.h>*

* Required for UNIX V compatibility.

For additional compatibility information, see Compatibility.


// 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);
    int result = _vcprintf_s(format, args);
    return result;

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).

See also

Stream I/O
vprintf Functions
_cprintf, _cprintf_l, _cwprintf, _cwprintf_l
fprintf, _fprintf_l, fwprintf, _fwprintf_l
printf, _printf_l, wprintf, _wprintf_l
sprintf, _sprintf_l, swprintf, _swprintf_l, __swprintf_l
va_arg, va_copy, va_end, va_start