-/*
-** Beginning in OpenVMS Version 7.0 mktime, time, ctime, strftime
-** have two implementations. One implementation is provided
-** for compatibility and deals with time in terms of local time,
-** the other __utc_* deals with time in terms of UTC.
-*/
-/* We use the same conditions as in said time.h to check if we should
- assume that t contains local time (and should therefore be adjusted)
- or UTC (and should therefore be left untouched). */
-#if __CRTL_VER < 70000000 || defined _VMS_V6_SOURCE
- /* Get the numerical value of the equivalence string */
- status = atoi(logvalue);
-
- /* and use it to move time to GMT */
- t -= status;
+ /*
+ ** Beginning in OpenVMS Version 7.0 mktime, time, ctime, strftime
+ ** have two implementations. One implementation is provided
+ ** for compatibility and deals with time in terms of local time,
+ ** the other __utc_* deals with time in terms of UTC.
+ */
+ /*
+ * We use the same conditions as in said time.h to check if we should
+ * assume that t contains local time (and should therefore be
+ * adjusted) or UTC (and should therefore be left untouched).
+ */
+# if __CRTL_VER < 70000000 || defined _VMS_V6_SOURCE
+ /* Get the numerical value of the equivalence string */
+ status = atoi(logvalue);
+
+ /* and use it to move time to GMT */
+ t -= status;
+# endif
+
+ /* then convert the result to the time structure */
+
+ /*
+ * Since there was no gmtime_r() to do this stuff for us, we have to
+ * do it the hard way.
+ */
+ {
+ /*-
+ * The VMS epoch is the astronomical Smithsonian date,
+ if I remember correctly, which is November 17, 1858.
+ Furthermore, time is measure in thenths of microseconds
+ and stored in quadwords (64 bit integers). unix_epoch
+ below is January 1st 1970 expressed as a VMS time. The
+ following code was used to get this number:
+
+ #include <stdio.h>
+ #include <stdlib.h>
+ #include <lib$routines.h>
+ #include <starlet.h>
+
+ main()
+ {
+ unsigned long systime[2];
+ unsigned short epoch_values[7] =
+ { 1970, 1, 1, 0, 0, 0, 0 };
+
+ lib$cvt_vectim(epoch_values, systime);
+
+ printf("%u %u", systime[0], systime[1]);
+ }
+ */
+ unsigned long unix_epoch[2] = { 1273708544, 8164711 };
+ unsigned long deltatime[2];
+ unsigned long systime[2];
+ struct vms_vectime {
+ short year, month, day, hour, minute, second, centi_second;
+ } time_values;
+ long operation;
+
+ /*
+ * Turn the number of seconds since January 1st 1970 to an
+ * internal delta time. Note that lib$cvt_to_internal_time() will
+ * assume that t is signed, and will therefore break on 32-bit
+ * systems some time in 2038.
+ */
+ operation = LIB$K_DELTA_SECONDS;
+ status = lib$cvt_to_internal_time(&operation, &t, deltatime);
+
+ /*
+ * Add the delta time with the Unix epoch and we have the current
+ * UTC time in internal format
+ */
+ status = lib$add_times(unix_epoch, deltatime, systime);
+
+ /* Turn the internal time into a time vector */
+ status = sys$numtim(&time_values, systime);
+
+ /* Fill in the struct tm with the result */
+ result->tm_sec = time_values.second;
+ result->tm_min = time_values.minute;
+ result->tm_hour = time_values.hour;
+ result->tm_mday = time_values.day;
+ result->tm_mon = time_values.month - 1;
+ result->tm_year = time_values.year - 1900;
+
+ operation = LIB$K_DAY_OF_WEEK;
+ status = lib$cvt_from_internal_time(&operation,
+ &result->tm_wday, systime);
+ result->tm_wday %= 7;
+
+ operation = LIB$K_DAY_OF_YEAR;
+ status = lib$cvt_from_internal_time(&operation,
+ &result->tm_yday, systime);
+ result->tm_yday--;
+
+ result->tm_isdst = 0; /* There's no way to know... */
+
+ ts = result;
+ }
+ }