1 files changed, 21 insertions, 0 deletions
diff --git a/demo4/child.py b/demo4/child.py
new file mode 100644
index 0000000..cbceb37
--- /dev/null
+++ b/demo4/child.py
@@ -0,0 +1,21 @@
+import posix_ipc
+import time
+import sys
+import random
+
+# The parent passes the semaphore's name to me.
+name = sys.argv[1]
+
+print('Child: waiting to aquire semaphore ' + name)
+
+with posix_ipc.Semaphore(name) as sem: 
+    print('Child: semaphore ' + sem.name + ' aquired; holding for 3 seconds.')
+
+    # Flip a coin to determine whether or not to bail out of the context.
+    if random.randint(0, 1):
+        print("Child: raising ValueError to demonstrate unplanned context exit")
+        raise ValueError
+
+    time.sleep(3)
+
+    print('Child: gracefully exiting context (releasing the semaphore).')