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SETSID(2)                  Linux Programmer's Manual                 SETSID(2)



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

SYNOPSIS
       #include <&lt;unistd.h>&gt;

       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
       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 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)