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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 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 father 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 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)