diff --git a/sync/sync_mac.v b/sync/sync_mac.v
new file mode 100644
index 0000000000..ab4fa03523
--- /dev/null
+++ b/sync/sync_mac.v
@@ -0,0 +1,15 @@
+module sync
+
+#include <pthread.h>
+struct Mutex {
+	mutex C.pthread_mutex_t
+}
+
+fn (m Mutex) lock() {
+	C.pthread_mutex_lock(&m.mutex)
+}
+
+fn (m Mutex) unlock() {
+	C.pthread_mutex_unlock(&m.mutex)
+}
+
diff --git a/sync/sync_win.v b/sync/sync_win.v
new file mode 100644
index 0000000000..aec69932d9
--- /dev/null
+++ b/sync/sync_win.v
@@ -0,0 +1,13 @@
+module sync
+
+struct Mutex {
+}
+
+fn (m Mutex) lock() {
+panic('not implemented') 
+}
+
+fn (m Mutex) unlock() {
+panic('not implemented') 
+}
+