Removed submodules

lab8-synch/pingpong.c

@@ -0,0 +1,94 @@
+#include <assert.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <semaphore.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "pingpong.h"
+
+typedef struct pparg {
+  sem_t *sem_ping; // Tell ping to wake up
+  sem_t *sem_pong; // Tell pong to wake up
+  size_t *shared;
+} ppargs_t;
+
+void *
+pong (void * _args)
+{
+  ppargs_t *args = (ppargs_t *) _args;
+
+  while (1)
+    {
+      sem_wait (args->sem_pong);
+
+      printf ("PONG!\n");
+
+      if (*(args->shared) == 0)
+        {
+          break;
+        }
+      else
+        {
+          sem_post (args->sem_ping);
+        }
+    }
+
+  printf ("PONG: Game over\n");
+  pthread_exit (NULL);
+}
+
+void
+ping (size_t *count)
+{
+  pthread_t pong_thread;
+  sem_t sem_ping;
+  sem_t sem_pong;
+
+  if (sem_init (&sem_ping, 0, 1) != 0)
+    {
+      perror ("sem_init sem_ping");
+      return;
+    }
+  if (sem_init (&sem_pong, 0, 0) != 0)
+    {
+      perror ("sem_init sem_pong");
+      sem_destroy (&sem_ping);
+      return;
+    }
+
+  ppargs_t args;
+  args.sem_ping = &sem_ping;
+  args.sem_pong = &sem_pong;
+  args.shared = count;
+
+  if (pthread_create (&pong_thread, NULL, pong, (void *)&args) != 0)
+    {
+      perror ("pthread_create");
+      sem_destroy (&sem_ping);
+      sem_destroy (&sem_pong);
+      return;
+    }
+
+  while (1)
+    {
+      sem_wait (&sem_ping);
+
+      (*count)--;
+      printf ("PING!\n");
+
+      sem_post (&sem_pong);
+
+      if (*count == 0)
+          break;
+    }
+
+  // After PONG prints game over and exits, do the same for PING
+  pthread_join (pong_thread, NULL);
+  printf ("PING: Game over\n");
+
+  sem_destroy (&sem_ping);
+  sem_destroy (&sem_pong);
+}