diff --git a/src/system/libroot/posix/time/Jamfile b/src/system/libroot/posix/time/Jamfile
index 4614429b6d..8d93807b8c 100644
--- a/src/system/libroot/posix/time/Jamfile
+++ b/src/system/libroot/posix/time/Jamfile
@@ -7,6 +7,7 @@ UsePrivateHeaders [ FDirName libroot time ] ;
 
 KernelMergeObject posix_time.o :
 	asctime.c
+	clock.c
 	ctime.c
 	difftime.c
 	localtime.c
diff --git a/src/system/libroot/posix/time/clock.c b/src/system/libroot/posix/time/clock.c
new file mode 100644
index 0000000000..fc16c9c463
--- /dev/null
+++ b/src/system/libroot/posix/time/clock.c
@@ -0,0 +1,22 @@
+/*
+ * Copyright 2005, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
+ * Distributed under the terms of the MIT License.
+ */
+
+
+#include <time.h>
+#include <OS.h>
+
+
+clock_t
+clock(void)
+{
+	thread_info info;
+	get_thread_info(find_thread(NULL), &info);
+
+	return (clock_t)((info.kernel_time + info.user_time) / 1000);
+		// unlike the XSI specs say, CLOCKS_PER_SEC is 1000 and not 1000000 in
+		// BeOS - that means we have to convert the bigtime_t to CLOCKS_PER_SEC
+		// before we return it
+}
+