DAEMON(3) Linux Programmer's Manual DAEMON(3)NAMEdaemon - 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 daemons.
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 stan‐
dard input, standard output and standard error to /dev/null.
RETURN VALUE
(This function forks, and if the fork() succeeds, the parent does
_exit(0), so that further errors are seen by the child only.) On suc‐
cess 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 ALSOfork(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.
CONFORMING TO
Not in POSIX.1-2001. A similar function appears on the BSDs. The dae‐
mon() function first appeared in 4.4BSD.
BSD MANPAGE 1993-06-09 DAEMON(3)