/sys$common/syshlp/helplib.hlb DCE_DTS, Application Routines, utc_cmpmidtime  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 NAME

   utc_cmpmidtime - Compares two binary timestamps or two relative binary
                    timestamps, ignoring inaccuracies

 SYNOPSIS

   #include <dce/utc.h>

   int utc_cmpmidtime( enum utc_cmptype *relation,
                       utc_t *utc1,
                       utc_t *utc2 );

 PARAMETERS

   Input

   utc1
       Binary timestamp or relative binary timestamp. Use NULL if you want
       this routine to use the current time for this parameter.

   utc2
       Binary timestamp or relative binary timestamp. Use NULL if you want
       this routine to use the current time for this parameter.

   Output

   relation
       Result of the comparison of utc1:utc2 where the result is an
       enumerated type with one of the following values:

         + utc_equalTo

         + utc_lessThan

         + utc_greaterThan

 DESCRIPTION

   The utc_cmpmidtime() routine compares two binary timestamps and
   returns a flag indicating that the first timestamp is greater than,
   less than, or equal to the second timestamp. Inaccuracy information
   is ignored for this comparison; the input values are therefore
   equivalent to the midpoints of the time intervals described by the
   input binary timestamps.

   The input binary timestamps express two absolute or two relative times.
   Do not compare relative binary timestamps to absolute binary timestamps.
   If you do, no meaningful results and no errors are returned.

   The following routine does a lexical ordering on the time interval
   midpoints.

        utc1 is utc_lessThan utc2 iff
                utc1.time < utc2.time

        utc1 is utc_greaterThan utc2 iff
                utc1.time > utc2.time

        utc1 is utc_equalTo utc2 iff
                utc1.time == utc2.time

 RETURN VALUES

    0    Indicates that the routine executed successfully.

   -1    Indicates an invalid time argument.

 EXAMPLES

   The following example checks if the current time (ignoring inaccuracies)
   is after 13:00 local time.

        struct tm           tmtime, tmzero;
        enum utc_cmptype    relation;
        utc_t               testtime;

        /*   Zero the tm structure for inaccuracy...        */
        memset(&tmzero, 0, sizeof(tmzero));

        /*   Get the current time, mapped to a tm structure...
         *
         *        NOTE:  The NULL argument is used to get the current
         *               time.
         */
        utc_localtime(&tmtime,      /* Out: Current local time in tm
                                            struct                      */
                     (long *)0,     /* Out: Nanoseconds of time         */
                     (struct tm *)0,/* Out: Current inacc in tm struct  */
                     (long *)0,     /* Out: Nanoseconds of inaccuracy   */
                     (utc_t *)0);   /* In:  Current timestamp           */

         /*   Alter the tm structure to correspond to 13:00 local time. */
        tmtime.tm_hour = 13;
        tmtime.tm_min = 0;
        tmtime.tm_sec = 0;

         /*   Convert to a binary timestamp...         */
        utc_mklocaltime(&testtime, /* Out: Binary timestamp of 13:00    */
                        &tmtime,   /* In:  13:00 in tm struct           */
                        0,         /* In:  Nanoseconds of time          */
                        &tmzero,   /* In:  Zero inaccuracy in tm struct */
                        0);        /* In:  Nanoseconds of inaccuracy    */

      /* Compare to the current time. Note the use of the NULL argument */
        utc_cmpmidtime(&relation,   /* Out: Comparison relation         */
                       (utc_t *)0,  /* In:  Current timestamp           */
                       &testtime);  /* In:  13:00 local time timestamp  */

        /*   If the time is not later - wait, print a message, etc.     */
        if (relation != utc_greaterThan) {

         /*          It is not later then 13:00 local time. Note that
          *          this depends on the setting of the user's environment.
          */
        }

 RELATED INFORMATION

   Functions: utc_cmpintervaltime