Index: /trunk/src/VBox/Runtime/r3/os2/RTTimeSet-os2.cpp
===================================================================
--- /trunk/src/VBox/Runtime/r3/os2/RTTimeSet-os2.cpp	(revision 75297)
+++ /trunk/src/VBox/Runtime/r3/os2/RTTimeSet-os2.cpp	(revision 75297)
@@ -0,0 +1,87 @@
+/* $Id$ */
+/** @file
+ * IPRT - RTTimeSet, OS/2.
+ */
+
+/*
+ * Copyright (c) 2018 knut st. osmundsen <bird-src-spam@anduin.net>
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following
+ * conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define LOG_GROUP RTLOGGROUP_TIME
+#define INCL_DOSDATETIME
+#include <os2.h>
+
+#include <iprt/time.h>
+#include "internal/iprt.h"
+
+#include <iprt/err.h>
+
+
+RTDECL(int) RTTimeSet(PCRTTIMESPEC pTime)
+{
+    /*
+     * Convert to local time and explode it, keeping the distance
+     * between UTC and local.
+     */
+    int64_t    cNsLocalDelta = RTTimeLocalDeltaNanoFor(pTime);
+    RTTIMESPEC TimeLocal     = *pTime;
+    RTTIME     Exploded;
+    if (RTTimeExplode(&Exploded, RTTimeSpecAddNano(&TimeLocal, cNsLocalDelta))))
+    {
+        /*
+         * Fill in the OS/2 structure and make the call.
+         */
+        DATETIME DateTime;
+        DateTime.hour       = Exploded.u8Hour;
+        DateTime.minutes    = Exploded.u8Minute;
+        DateTime.seconds    = Exploded.u8Second;
+        DateTime.hundredths = (uint8_t)(Exploded.u32Nanosecond / (RT_NS_1SEC_64 / 100));
+        DateTime.day        = Exploded.u8MonthDay;
+        DateTime.month      = Exploded.u8Month;
+        DateTime.year       = (uint16_t)Exploded.i32Year;
+        DateTime.weekday    = Exploded.u8WeekDay;
+
+        /* Minutes from UTC.  http://www.edm2.com/os2api/Dos/DosSetDateTime.html says
+           that timezones west of UTC should have a positive value.  The kernel fails
+           the call if we're more than +/-780 min (13h) distant, so clamp it in
+           case of bogus TZ values. */
+        DateTime.timezone   = (int16_t)(-cNsLocalDelta / RT_NS_1MIN);
+        if (DateTime.timezone > 780)
+            DateTime.timezone = 780;
+        else if (DateTime.timezone < -780)
+            DateTime.timezone = -780;
+
+        APIRET rc = DosSetDateTime(&DateTime);
+        if (rc == NO_ERROR)
+            return VINF_SUCCESS;
+        AssertRC(rc);
+        return RTErrConvertFromOS2(rc);
+    }
+    return VERR_INVALID_PARAMETER;
+}
+