SETSID(2)		   Linux Programmers Manual		    SETSID(2)



NAME
       setsid - creates a session and sets the process group ID

SYNOPSIS
       #include 

       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 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.

RETURN VALUE
       The session ID of the calling process.

ERRORS
       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.

CONFORMING TO
       SVr4, POSIX.1-2001.

NOTES
       A child created via fork(2) inherits its parents 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().

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

COLOPHON
       This page is part of release 3.05 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				  1994-08-27			     SETSID(2)