Default FDs

arvind_tyche · 06-24-2004, 02:21 AM

Hello,

I would like to know how do I change the default file descriptor for a process for a FD which I define..? I think of redirecting all the Outputs of the process to a file.

Thanks .....

Bye...

ToniT · 06-24-2004, 06:53 AM

"default file descriptor"? You mean stdout and stderr? To replace those for a process, you can 'close' the old ones and 'dup'(licate) others into their place.

aluser · 06-24-2004, 10:02 AM

If you want to redirect stdin, stdout, and stderr, the function you want is probably dup2(). e.g.

Code:

int fd;
fd = open("/dev/null", O_WRONLY);
if (fd < 0)
    err(EXIT_FAILURE, "crap");
if (dup2(fd, fileno(stdout)) < 0)
    err(EXIT_FAILURE, "dup2");
/* now stdout goes to /dev/null */