explain_setpgid_or_die - set process group and report errors

       libexplain version 1.4
       Copyright (C) 2011 Peter Miller

                                                                                       explain_setpgid_or_die(3)

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

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

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

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

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

       explain_setpgid_or_die - set process group and report errors

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

       The explain_setpgid_on_error function always returns the value return by the  wrapped  setpgid(2)  system
       call.

setpgid(2)
               set process group

       explain_setpgid(3)
               explain setpgid(2) errors

       exit(2) terminate the calling process

       #include <libexplain/setpgid.h>
       void explain_setpgid_or_die(pid_t pid, pid_t pgid);
       int explain_setpgid_on_error(pid_t pid, pid_t pgid);