explain_setsid_or_die(3) [debian man page]

explain_setsid_or_die(3)				     Library Functions Manual					  explain_setsid_or_die(3)

NAME

       explain_setsid_or_die - sets process group ID and report errors

SYNOPSIS

       #include <libexplain/setsid.h>
       pid_t explain_setsid_or_die(void);
       pid_t explain_setsid_on_error(void);

DESCRIPTION

       The explain_setsid_or_die function is used to call the setsid(2) system call. On failure an explanation will be printed to stderr, obtained
       from the explain_setsid(3) function, and then the process terminates by calling exit(EXIT_FAILURE).

       The explain_setsid_on_error function is used to call the setsid(2) system call. On failure  an  explanation  will  be  printed  to  stderr,
       obtained from the explain_setsid(3) function, but still returns to the caller.

RETURN VALUE

       The  explain_setsid_or_die  function  only  returns  on	success, see setsid(2) for more information. On failure, prints an explanation and
       exits, it does not return.

       The explain_setsid_on_error function always returns the value return by the wrapped setsid(2) system call.

EXAMPLE

       The explain_setsid_or_die function is intended to be used in a fashion similar to the following example:
	      explain_setsid_or_die();

SEE ALSO

       setsid(2)
	       creates a session and sets the process group ID

       explain_setsid(3)
	       explain setsid(2) errors

       exit(2) terminate the calling process

COPYRIGHT

       libexplain version 0.52
       Copyright (C) 2011 Peter Miller

															  explain_setsid_or_die(3)

setsid(2)							   System Calls 							 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, if the calling process is not a process group leader. Upon return the calling process will be
       the session leader of this new session, will be the process group leader of a new process group, and will have no controlling terminal. The
       process	group	ID of the calling process will be set equal to the process ID of the calling process. The calling process will be the only
       process in the new process group and the only process in the new session.

RETURN VALUES

       Upon successful completion, setsid() returns the value of the process group  ID of the calling process. Otherwise it returns (pid_t)-1  and
       sets errno to indicate the error.

ERRORS

       The setsid() function will fail if:

       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.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |Async-Signal-Safe 	   |
       +-----------------------------+-----------------------------+

SEE ALSO

       getsid(2), setpgid(2), setpgrp(2), attributes(5), standards(5)

WARNINGS

       A call to setsid() by a process that is a process group leader will fail. A process can become a process group leader  by  being  the  last
       member of a pipeline started by a job control shell. Thus, a process that expects to be part of a pipeline, and that calls setsid(), should
       always first fork; the parent should exit and the child should call setsid(). This will ensure that the calling process will work  reliably
       when started by both job control shells and non-job control shells.

SunOS 5.11							    21 Aug 2002 							 setsid(2)