Data commit

Task/Mutex/Python/mutex.py

@@ -0,0 +1,30 @@
+import threading
+from time import sleep
+
+# res: max number of resources. If changed to 1, it functions
+# identically to a mutex/lock object
+res = 2
+sema = threading.Semaphore(res)
+
+class res_thread(threading.Thread):
+    def run(self):
+        global res
+        n = self.getName()
+        for i in range(1, 4):
+            # acquire a resource if available and work hard
+            # for 2 seconds.  if all res are occupied, block
+            # and wait
+            sema.acquire()
+            res = res - 1
+            print n, "+  res count", res
+            sleep(2)
+
+                        # after done with resource, return it to pool and flag so
+            res = res + 1
+            print n, "-  res count", res
+            sema.release()
+
+# create 4 threads, each acquire resorce and work
+for i in range(1, 5):
+    t = res_thread()
+    t.start()