setsid(2)

1SETSID(2)                  Linux Programmer's Manual                 SETSID(2)
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NAME

6       setsid - creates a session and sets the process group ID
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SYNOPSIS

9       #include <unistd.h>
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11       pid_t setsid(void);
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DESCRIPTION

14       setsid()  creates a new session if the calling process is not a process
15       group leader.  The calling process is the leader of  the  new  session,
16       the  process group leader of the new process group, and has no control‐
17       ling terminal.  The process group ID and  session  ID  of  the  calling
18       process are set to the PID of the calling process.  The calling process
19       will be the only process in this new process group and in this new ses‐
20       sion.
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RETURN VALUE

23       On  success,  the  (new) session ID of the calling process is returned.
24       On error, (pid_t) -1 is returned, and errno  is  set  to  indicate  the
25       error.
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ERRORS

28       EPERM  The  process group ID of any process equals the PID of the call‐
29              ing process.  Thus, in particular, setsid() fails if the calling
30              process is already a process group leader.
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CONFORMING TO

33       SVr4, POSIX.1-2001.
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NOTES

36       A child created via fork(2) inherits its parent's session ID.  The ses‐
37       sion ID is preserved across an execve(2).
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39       A process group leader is a process with process group ID equal to  its
40       PID.   In  order  to  be  sure  that setsid() will succeed, fork(2) and
41       _exit(2), and have the child do setsid().
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COLOPHON

48       This  page  is  part of release 3.53 of the Linux man-pages project.  A
49       description of the project, and information about reporting  bugs,  can
50       be found at http://www.kernel.org/doc/man-pages/.
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54Linux                             2013-02-11                         SETSID(2)