explain_setgid_or_die - set group identity and report errors

       libexplain version 1.4
       Copyright (C) 2012 Peter Miller

                                                                                        explain_setgid_or_die(3)

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

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

       gid     The gid, exactly as to be passed to the setgid(2) system call.

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

       explain_setgid_or_die - set group identity and report errors

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

       The explain_setgid_on_error function always returns the value return  by  the  wrapped  setgid(2)  system
       call.

setgid(2)
               set group identity

       explain_setgid(3)
               explain setgid(2) errors

       exit(2) terminate the calling process

       #include <libexplain/setgid.h>
       void explain_setgid_or_die(gid_t gid);
       int explain_setgid_on_error(gid_t gid);