freopen

Syntax

#include <stdio.h> FILE *freopen(const char *filename, const char *mode, FILE *file);

Description

This function closes file if it was open, then opens a new file like fopen(filename, mode) (see section fopen) but it reuses file.

This is useful to, for example, associate stdout with a new file.

Return Value

The new file, or NULL on error.

Portability

ANSI/ISO C	C89; C99
POSIX	1003.2-1992; 1003.1-2001

Example

freopen("/tmp/stdout.dat", "wb", stdout);