Provided by: manpages-dev_2.62-1_all
setsid - creates a session and sets the process group ID
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 control‐
ling tty. 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.
The session ID of the calling process.
On error, -1 is returned, and errno is set. The only error which can
happen is EPERM. It is returned when the process group ID of any pro‐
cess equals the PID of the calling process. Thus, in particular, set
sid() fails if the calling process is already a process group leader.
A child created via fork(2) inherits its parent’s session ID. The ses‐
sion 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().
setpgid(2), setpgrp(2), tcgetsid(3)