diff --git a/clock.cabal b/clock.cabal
--- a/clock.cabal
+++ b/clock.cabal
@@ -1,25 +1,27 @@
 name:          clock
-version:       0.3
+version:       0.4.0.1
 stability:     stable
 synopsis:      High-resolution clock functions: monotonic, realtime, cputime.
 description:   A package for convenient access to high-resolution clock and
-               timer functions of different operating systems.
+               timer functions of different operating systems via a unified API.
                .
-               POSIX layer was developed by Cetin Sert in 2009.
+               POSIX code and surface API was developed by Cetin Sert in 2009.
                .
-               Windows layer was contributed by Eugene Kirpichov in 2010.
+               Windows code was contributed by Eugene Kirpichov in 2010.
                .
-               Both layers share the same surface API.
+               FreeBSD code was contributed by Finn Espen Gundersen on 2013-10-14.
                .
+               OS X code was contributed by Gerolf Seitz on 2013-10-15.
+               .
                [Version Scheme]
                Major-@/R/@-ewrite . New-@/F/@-unctionality . @/I/@-mprovementAndBugFixes . @/P/@-ackagingOnly
                .
                * @PackagingOnly@ changes are made for quality assurance reasons.
 
-copyright:     Copyright © Cetin Sert 2009-2012, Eugene Kirpichov 2010
+copyright:     Copyright © Cetin Sert 2009-2013, Eugene Kirpichov 2010, Finn Espen Gundersen 2013, Gerolf Seitz 2013
 license:       BSD3
 license-file:  LICENSE
-author:        Cetin Sert <cetin@corsis.eu>, Corsis Research; Eugene Kirpichov <ekirpichov@gmail.com>
+author:        Cetin Sert <cetin@corsis.eu>, Corsis Research
 maintainer:    Cetin Sert <cetin@corsis.eu>, Corsis Research
 homepage:      http://corsis.github.com/clock/
 bug-reports:   http://corsis.github.com/clock/issues
diff --git a/csec/clock.c b/csec/clock.c
--- a/csec/clock.c
+++ b/csec/clock.c
@@ -119,12 +119,43 @@
 // ***********************
 
 #include <time.h>
+#ifdef __MACH__
+  #include <mach/clock.h>
+  #include <mach/mach.h>
+  #define CLOCK_ID_T clock_id_t
+  #define CLOCK_MONOTONIC SYSTEM_CLOCK
+  #define CLOCK_REALTIME CALENDAR_CLOCK
+  #define CLOCK_PROCESS_CPUTIME_ID SYSTEM_CLOCK
+  #define CLOCK_THREAD_CPUTIME_ID SYSTEM_CLOCK
+#else
+  #define CLOCK_ID_T clockid_t
+#endif
 
-void time_(clockid_t clock, long* t)
+// due to missing define in FreeBSD 9.0 and 9.1 (http://lists.freebsd.org/pipermail/freebsd-stable/2013-September/075095.html)
+#ifndef CLOCK_PROCESS_CPUTIME_ID
+  #define CLOCK_PROCESS_CPUTIME_ID 15
+#endif
+
+void time_(CLOCK_ID_T clock, long* t)
 {
+  #ifdef __MACH__
+    // OS X does not have clock_gettime, use clock_get_time
+    // see http://stackoverflow.com/questions/11680461/monotonic-clock-on-osx
+    clock_serv_t cclock;
+    mach_timespec_t mts;
+    struct timespec* ts;
+    host_get_clock_service(mach_host_self(), clock, &cclock);
+    clock_get_time(cclock, &mts);
+    mach_port_deallocate(mach_task_self(), cclock);
+    ts = (struct timespec*)t;
+    ts->tv_sec = mts.tv_sec;
+    ts->tv_nsec = mts.tv_nsec;
+  #else
+    clock_gettime(clock, (struct timespec*)t);
+  #endif
 
-  clock_gettime(clock, (struct timespec*)t);
 
+
 /*struct timespec a;
 
   clock_gettime(clock, &a);
@@ -155,10 +186,18 @@
 }
 
 
-void res_(clockid_t clock, long* t)
+void res_(CLOCK_ID_T clock, long* t)
 {
-
-  clock_getres(clock, (struct timespec*)t);
+  #ifdef __MACH__
+    clock_serv_t cclock;
+    int nsecs;
+    mach_msg_type_number_t count;
+    host_get_clock_service(mach_host_self(), clock, &cclock);
+    clock_get_attributes(cclock, CLOCK_GET_TIME_RES, (clock_attr_t)&nsecs, &count);
+    mach_port_deallocate(mach_task_self(), cclock);
+  #else
+    clock_getres(clock, (struct timespec*)t);
+  #endif
 
 /*struct timespec a;