Prints formatted data to a stream.

#include <stdio.h>

int fprintf (FILE *stream, const char *format[, argument]...);
int fprintf_s(FILE *stream, const char *format[, argument]...);

#include <wchar.h>

int fwprintf(FILE *stream, const wchar_t *format[, argument]...);
int fwprintf_s(FILE *stream, const wchar_t *format[, argument]...);

Parameters

stream

Pointer to FILE structure represeting the output stream.

format

Formatted string consisting of ordinary characters, escape sequences, and (if arguments follow) format specifications.

argument

Optional arguments.

Remarks

The ordinary characters and escape sequences are copied to stream in order of their appearance.

The format and optional arguments have the same form and function as described in printf.

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

fprintf_s and fwprintf_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 printed.

Success.

A negative value.

Failure.

Generic Text Routines

Requirements