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, the
process group leader of the new process group, and has no
controlling 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.
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 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 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)
|