setsid — creates a session and sets the process group ID
#include <unistd.h>
pid_t
setsid( |
void); |
setsid() creates a new
session if the calling process is not a process group leader.
The calling process is the leader of the new session (i.e.,
its session ID is made the same as its process ID). The
calling process also becomes the process group leader of a
new process group in the session (i.e., its process group ID
is made the same as its process ID).
The calling process will be the only process in the new process group and in the new session. The new session has no controlling terminal.
On success, the (new) session ID of the calling process is
returned. On error, (pid_t)
−1 is returned, and errno is set to indicate the error.
The process group ID of any process equals the PID
of the calling process. Thus, in particular,
setsid() fails if the
calling process is already a process group leader.
A child created via fork(2) inherits its parent's session ID. The session ID is preserved across an execve(2).
A process group leader is a process whose process group ID
equals its PID. Disallowing a process group leader from
calling setsid() prevents the
possibility that a process group leader places itself in a
new session while other processes in the process group remain
in the original session; such a scenario would break the
strict two-level hierarchy of sessions and process groups. In
order to be sure that setsid()
will succeed, fork(2) and _exit(2), and have the
child do setsid().
This page is part of release 4.07 of the Linux man-pages project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man−pages/.
|
Copyright Michael Haardt (michaelcantor.informatik.rwth-aachen.de) Sat Aug 27 20:43:50 MET DST 1994 and Copyright (C) 2014, Michael Kerrisk <mtk.manpagesgmail.com> %%%LICENSE_START(GPLv2+_DOC_FULL) This is free documentation; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The GNU General Public License's references to "object code" and "executables" are to be interpreted as the output of any document formatting or typesetting system, including intermediate and printed output. This manual is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this manual; if not, see <http://www.gnu.org/licenses/>. %%%LICENSE_END Modified Sun Sep 11 19:19:05 1994 <faithcs.unc.edu> Modified Mon Mar 25 10:19:00 1996 <aebcwi.nl> (merged a few tiny changes from a man page by Charles Livingston). Modified Sun Jul 21 14:45:46 1996 <aebcwi.nl> |