explain_setpgrp_or_die - set process group and report errors

       libexplain version 1.4
       Copyright (C) 2011 Peter Miller

                                                                                       explain_setpgrp_or_die(3)

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

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

       pid     The pid, exactly as to be passed to the setpgrp(2) system call.

       pgid    The pgid, exactly as to be passed to the setpgrp(2) system call.

       Note:  the setpgrp(2) function has two implementations.  The System V version has no arguments, while the
       BSD version has two arguments.  For simplicity of implementation, the argument list  seen  here  includes
       the pid and pgid arguments.

       The  System  V  getpgid()  semantics  can  be  obtained  by calling setpgrp(0, 0) on systems with the BSD
       version, and this is the API for libexplain, even on systems that do not use the BSD API.

       The explain_setpgrp_or_die function is intended to be used in a fashion similar to the following example:
              explain_setpgrp_or_die(pid, pgid);

       explain_setpgrp_or_die - set process group and report errors

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

       The  explain_setpgrp_on_error  function  always returns the value return by the wrapped setpgrp(2) system
       call.

setpgrp(2)
               set process group

       explain_setpgrp(3)
               explain setpgrp(2) errors

       exit(2) terminate the calling process

       #include <libexplain/setpgrp.h>
       void explain_setpgrp_or_die(pid_t pid, pid_t pgid);
       int explain_setpgrp_on_error(pid_t pid, pid_t pgid);