DAEMON(3) Linux Programmer's Manual DAEMON(3)
NAME
daemon - run in the background
SYNOPSIS
#include <unistd.h>
int daemon(int nochdir, int noclose);
DESCRIPTION
The daemon() function is for programs wishing to detach themselves from the controlling terminal and run in the background as system dae-
mons.
Unless the argument nochdir is non-zero, daemon() changes the current working directory to the root ("/").
Unless the argument noclose is non-zero, daemon() will redirect standard input, standard output and standard error to /dev/null.
RETURN VALUE
(This function forks, and if the fork() succeeds, the father does _exit(0), so that further errors are seen by the child only.) On success
zero will be returned. If an error occurs, daemon() returns -1 and sets the global variable errno to any of the errors specified for the
library functions fork(2) and setsid(2).
SEE ALSO
fork(2), setsid(2)
NOTES
The glibc implementation can also return -1 when /dev/null exists but is not a character device with the expected major and minor numbers.
In this case errno need not be set.
HISTORY
The daemon() function first appeared in BSD4.4.
BSD MANPAGE
1993-06-09 DAEMON(3)
