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 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.

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  suc-
       ceed, fork(2) and _exit(2), and have the child do setsid().

SEE ALSO
       getsid(2), setpgid(2), setpgrp(2), tcgetsid(3), credentials(7)

COLOPHON
       This  page  is  part of release 3.25 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                                                      2008-12-03                                                  SETSID(2)