The following example computes the earliest and latest times for
    an array of 10 timestamps.

    utc_t               time_array[10], testtime, earliest, latest;
    int                 i;

    /*
     *   Set the running timestamp to the first entry...
     */

    testtime = time_array[0];

    for (i=1; i<10; i++) {

       /*
        *   Compute the minimum and the maximum against the next
        *   element...
        */

    utc_spantime(&testtime,       /* Out: Resultant interval        */
                 &testtime,       /* In:  Largest previous interval */
                 &time_array[i]); /* In:  Element under test        */
    }

    /*
     *   Compute the earliest possible time...
     */

    utc_pointtime(&earliest,    /* Out: Earliest poss time in array */
                 (utc_t *)0,    /* Out: Midpoint                    */
                 &latest,       /* Out: Latest poss time in array   */
                 &testtime);    /* In:  Spanning interval           */