setsid(2) System Calls setsid(2)NAMEsetsid - create session and set process group ID
SYNOPSIS
#include <sys/types.h>
#include <unistd.h>
pid_t setsid(void);
DESCRIPTION
The setsid() function creates a new session, if the calling process is
not a process group leader. Upon return the calling process will be the
session leader of this new session, will be the process group leader of
a new process group, and will have no controlling terminal. The process
group ID of the calling process will be set equal to the process ID of
the calling process. The calling process will be the only process in
the new process group and the only process in the new session.
RETURN VALUES
Upon successful completion, setsid() returns the value of the process
group ID of the calling process. Otherwise it returns (pid_t)−1 and
sets errno to indicate the error.
ERRORS
The setsid() function will fail if:
EPERM The calling process is already a process group leader,
or the process group ID of a process other than the
calling process matches the process ID of the calling
process.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Standard │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │Async-Signal-Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOgetsid(2), setpgid(2), setpgrp(2), attributes(5), standards(5)WARNINGS
A call to setsid() by a process that is a process group leader will
fail. A process can become a process group leader by being the last
member of a pipeline started by a job control shell. Thus, a process
that expects to be part of a pipeline, and that calls setsid(), should
always first fork; the parent should exit and the child should call
setsid(). This will ensure that the calling process will work reliably
when started by both job control shells and non-job control shells.
SunOS 5.10 21 Aug 2002 setsid(2)
