SETSID(2-SVR4)      RISC/os Reference Manual       SETSID(2-SVR4)



NAME
     setsid - set session ID

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

     pidt setsid(void);

DESCRIPTION
     If the calling process is not already a process group
     leader, setsid sets the process group ID and session ID i of
     the calling process to the process ID of the calling pro-
     cess, and releases the process's controlling terminal.

     setsid will fail and return an error if the following is
     true:

     EPERM          The calling process is already a process
                    group leader, or there are processes other
                    than the calling process whose process group
                    ID is equal to the process ID of the calling
                    process.

SEE ALSO
     intro(2), exec(2), exit(2), fork(2), getpid(2), getpgid(2),
     getsid(2), setpgid(2), setpgrp, signal(2), sigsend(2).

WARNING
     If the calling process is the last member of a pipeline
     started by a job control shell, the shell may make the cal-
     ling process a process group leader.  The other processes of
     the pipeline become members of that process group. In this
     case, the call to setsid will fail.  For this reason, a pro-
     cess that calls setsid and expects to be part of a pipeline
     should always first fork; the parent should exit and the
     child should call setsid, thereby insuring that the process
     will work reliably when started by both job control shells
     and non-job control shells.

DIAGNOSTICS
     Upon successful completion, setsid returns the calling
     process's session ID. Otherwise, a value of -1 is returned
     and errno is set to indicate the error.











                        Printed 11/19/92                   Page 1