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 3.54 of the Linux man-pages project.  A  description  of  the  project,  and
       information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.

Linux                                              2013-02-11                                          SETSID(2)