explain_getresgid_or_die - get r/e/s group IDs and report errors

       libexplain version 1.4
       Copyright (C) 2012 Peter Miller

                                                                                     explain_getresgid_or_die(3)

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

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

       rgid    The rgid, exactly as to be passed to the getresgid(2) system call.

       egid    The egid, exactly as to be passed to the getresgid(2) system call.

       sgid    The sgid, exactly as to be passed to the getresgid(2) system call.

       The explain_getresgid_or_die function is intended to be used  in  a  fashion  similar  to  the  following
       example:
              explain_getresgid_or_die(rgid, egid, sgid);

       explain_getresgid_or_die - get r/e/s group IDs and report errors

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

       The  explain_getresgid_on_error  function  always  returns  the  value return by the wrapped getresgid(2)
       system call.

getresgid(2)
               get real, effective and saved group IDs

       explain_getresgid(3)
               explain getresgid(2) errors

       exit(2) terminate the calling process

       #include <libexplain/getresgid.h>
       void explain_getresgid_or_die(gid_t *rgid, gid_t *egid, gid_t *sgid);
       int explain_getresgid_on_error(gid_t *rgid, gid_t *egid, gid_t *sgid);