setsid(2) [opendarwin man page]

SETSID(2)						      BSD System Calls Manual							 SETSID(2)

NAME

     setsid -- create session and set process group ID

SYNOPSIS

     #include <sys/types.h>
     #include <unistd.h>

     pid_t
     setsid(void);

DESCRIPTION

     The setsid function creates a new session.  The calling process is the session leader of the new session, is the process group leader of a
     new process group and has no controlling terminal.  The calling process is the only process in either the session or the process group.

     Upon successful completion, the setsid function returns the value of the process group ID of the new process group, which is the same as the
     process ID of the calling process.

ERRORS

     If an error occurs, setsid returns -1 and the global variable errno is set to indicate the error, as follows:

     [EPERM]		The calling process is already a process group leader, or the process group ID of a process other than the calling process
			matches the process ID of the calling process.

SEE ALSO

     setpgid(3), tcgetpgrp(3), tcsetpgrp(3)

STANDARDS

     The setsid function is expected to be compliant with the IEEE Std 1003.1-1988 (``POSIX.1'') specification.

BSD
								   June 4, 1993 							       BSD

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 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 3.53 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)