Disabled external gits

cs453-ca/CS453-2021-project/sync-examples/lock.h

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+#pragma once
+
+#include <pthread.h>
+#include <stdbool.h>
+
+/**
+ * @brief A lock that can only be taken exclusively. Contrarily to shared locks,
+ * exclusive locks have wait/wake_up capabilities.
+ */
+struct lock_t {
+    pthread_mutex_t mutex;
+    pthread_cond_t cv;
+};
+
+/** Initialize the given lock.
+ * @param lock Lock to initialize
+ * @return Whether the operation is a success
+**/
+bool lock_init(struct lock_t* lock);
+
+/** Clean up the given lock.
+ * @param lock Lock to clean up
+**/
+void lock_cleanup(struct lock_t* lock);
+
+/** Wait and acquire the given lock.
+ * @param lock Lock to acquire
+ * @return Whether the operation is a success
+**/
+bool lock_acquire(struct lock_t* lock);
+
+/** Release the given lock.
+ * @param lock Lock to release
+**/
+void lock_release(struct lock_t* lock);
+
+/** Wait until woken up by a signal on the given lock.
+ *  The lock is released until lock_wait completes at which point it is acquired
+ *  again. Exclusive lock access is enforced.
+ * @param lock Lock to release (until woken up) and wait on.
+**/
+void lock_wait(struct lock_t* lock);
+
+/** Wake up all threads waiting on the given lock.
+ * @param lock Lock on which other threads are waiting.
+**/
+void lock_wake_up(struct lock_t* lock);