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 standard
input, standard output and standard error to /dev/null
.
RETURN VALUE
(This function forks, and if the fork(2) succeeds, the
parent 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 fork(2) and setsid(2).
CONFORMING TO
Not in POSIX.1-2001. A similar function appears on the
BSDs. The daemon
() function
first appeared in 4.4BSD.
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.
SEE ALSO
fork(2), setsid(2)
Copyright (c) 1993
The Regents of the University of California. All rights reserved.
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must display the following acknowledgement:
This product includes software developed by the University of
California, Berkeley and its contributors.
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@(#)daemon.3
8.1 (Berkeley) 6/9/93
Added mentioning of glibc weirdness wrt unistd.h. 5/11/98, Al Viro
|