Formats and sends data to the stdout stream.

#include <stdio.h>
#include <stdarg.h>

int vprintf(const char *format, va_list ap);
int vprintf_s(const char *format, va_list ap);

#include <wchar.h>
#include <stdarg.h>

int vwprintf(const char *format, va_list ap);
int vwprintf_s(const char *format, va_list ap);

Parameters

format

Formatted string. This parameter has the same form and function as in printf.

ap

Pointer to list of arguments. This parameter has type va_list and points to a list of arguments that are converted and output according to the corresponding format specifications in format.

Remarks

These functions are similar to their counterparts printf and wprintf, but each accepts a pointer to a variable-argument list instead of additional arguments.

vwprintf is a wide-character version of vprintf; format is a wide-character string. vwprintf and vprintf behave identically if the stream is opened in ANSI mode. vprintf does not currently support output into a UNICODE stream.

vprintf_s and vwprintf_s perform parameter validation. If format is NULL then the function returns -1 and errno is set to EINVAL.

Return Values

The number of characters written, not counting the terminating null character.

Success.

A negative value if an output error occurs.

Failure.

Generic Text Routines

Requirements