Gets the time zone label for GMT.

    Format

      #include <utc.h>

      int utc_gmtzone(*tzname, tzlen, *tdf, *isdst, *utc)

         char *tzname;
         size_t tzlen;
         long *tdf;
         int *isdst;
         const utc_t *utc;

1 - Parameters

    Input

 tzlen

    Length of buffer tzname.

 utc

    Binary timestamp. This parameter is ignored.

    Output

 tzname

    Character string long enough to hold the time zone label.

 tdf

    Longword with differential in seconds east or west of GMT. A
    value of zero is always returned.

 isdst

    Integer with a value of zero, indicating that daylight saving
    time is not in effect. A value of zero is always returned.

2 - Description

    The Greenwich Mean Time Zone routine gets the time zone label
    and zero offset from GMT. Outputs are always tdf = 0 and tzname
    anyzone) and the Local Zone (utc_localzone) routines.

3 - Notes

    All of the output parameters are optional. No value is returned
    and no error occurs if the tzname pointer is NULL.

4 - Returns

     0   Indicates that the routine executed successfully (always
         returned).

5 - Example

    The following example prints out the current time in both local
    time and GMT time.

    utc_t       now;
    struct tm   tmlocal, tmgmt;
    long        tzoffset;
    int         tzdaylight;
    char        tzlocal[80], tzgmt[80];

    /*
     *   Get the current time once, so both conversions use the same
     *   time...
     */

    utc_gettime(&now);

    /*
     *   Convert to local time, using the process TZ environment
     *   variable...
     */

    utc_localtime(&tmlocal,       /* Out: Local time tm structure  */
                  (long *)0,      /* Out: Nanosec of time          */
                  (struct tm *)0, /* Out: Inaccuracy tm structure  */
                  (long *)0,      /* Out: Nanosec of inaccuracy    */
                  &now);          /* In:  Current binary timestamp */

    /*
     *   Get the local time zone name, offset from GMT, and current
     *   daylight savings flag...
     */

    utc_localzone(tzlocal,     /* Out: Local time zone name          */
                  80,          /* In:  Length of loc time zone name  */
                  &tzoffset,   /* Out: Loc time zone offset in secs  */
                  &tzdaylight, /* Out: Local time zone daylight flag */
                  &now);       /* In:  Current binary timestamp      */

    /*
     *   Convert to GMT...
     */

    utc_gmtime(&tmgmt,         /* Out: GMT tm structure              */
               (long *)0,      /* Out: Nanoseconds of time           */
               (struct tm *)0, /* Out: Inaccuracy tm structure       */
               (long *)0,      /* Out: Nanoseconds of inaccuracy     */
               &now);          /* In:  Current binary timestamp      */

    /*
     *   Get the GMT time zone name...
     */

    utc_gmtzone(tzgmt,         /* Out: GMT time zone name            */
                80,            /* In:  Size of GMT time zone name    */
                (long *)0,     /* Out: GMT time zone offset in secs  */
                (int *)0,      /* Out: GMT time zone daylight flag   */
                &now);         /* In:  Current binary timestamp      */

    /*
     *   Print out times and time zone information in the following
     *   format:
     *
     *          12:00:37 (EDT) = 16:00:37 (GMT)
     *          EDT is -240 minutes ahead of Greenwich Mean Time.
     *          Daylight savings time is in effect.
     */

    printf("%d:%02d:%02d (%s) = %d:%02d:%02d (%s)\n",
           tmlocal.tm_hour, tmlocal.tm_min, tmlocal.tm_sec, tzlocal,
           tmgmt.tm_hour, tmgmt.tm_min, tmgmt.tm_sec, tzgmt);
    printf("%s is %d minutes ahead of Greenwich Mean Time\n",
           tzlocal, tzoffset/60);
    if (tzdaylight != 0)
        printf("Daylight savings time is in effect\n");

6 - Related Functions

    utc_anyzone, utc_gmtime, utc_localzone