/*
         *      getdtablesize --
         *
         *      Several possibilites here. Note that while one
         *      can emulate getdtablesize with getrlimit on SVR4
         *      or 4.3BSD (or later), these systems should be
         *      POSIX.1 compliant, so sysconf is preferred.
         *
         */

        #ifdef  _SC_OPEN_MAX            /* POSIX -- preferred */
                if ((tableSize = sysconf(_SC_OPEN_MAX)) == -1) {
                        perror("sysconf");
                        ...
                }
        #elif   RLIMIT_NOFILE           /* who is non POSIX but has this? */
                if (getrlimit(RLIMIT_NOFILE, &rlimit) == -1) {
                        perror("getrlimit");
                        exit(1);
                }
                tableSize = rlimit.rlim_max;
        #else                           /* assume old BSD type */
                tableSize = getdtablesize();
        #endif