Redirecting stdout to a file in C through code

I am outputting to stdout. How can I redirect that to a new file through code? While we run the program we can redirect like ./sample > test.txt. How can I do this when executing t开发者_如何学Pythonhe sample program itself ? (C programming)

You probably want to use freopen.

Example from reference:

#include <stdio.h>
...
FILE *fp;
...
fp = freopen ("/tmp/logfile", "a+", stdout);

Use freopen().

Use dup2() system call and redirect the output to a file.