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SETSID(2) Linux Programmer's Manual SETSID(2)
NAME
setsid - creates a session and sets the process group ID
SYNOPSIS
#include <unistd.h>
pid_t setsid(void);
DESCRIPTION
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, the process group leader of the new
process group, and has no controlling terminal. The process group ID and session ID of
the calling process are set to the PID of the calling process. The calling process will
be the only process in this new process group and in this new session.
RETURN VALUE
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.
ERRORS
EPERM 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.
CONFORMING TO
SVr4, POSIX.1-2001.
NOTES
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 with process group ID equal to its PID. In order to
be sure that setsid() will succeed, fork(2) and _exit(2), and have the child do setsid().
SEE ALSO
setsid(1), getsid(2), setpgid(2), setpgrp(2), tcgetsid(3), credentials(7)
COLOPHON
This page is part of release 3.74 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 http://www.kernel.org/doc/man-pages/.
Linux 2013-02-11 SETSID(2)
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