@@ -35,11 +35,11 @@
 
 static of_mutex_t mutex;
 
 OF_CONSTRUCTOR()
 {
-	if (!of_mutex_new(&mutex))
+	if (of_mutex_new(&mutex) != 0)
 		OBJC_ERROR("Failed to create mutex!");
 }
 #endif
 
 int
@@ -49,46 +49,46 @@
 		return 0;
 
 #ifdef OF_HAVE_THREADS
 	struct lock_s *lock;
 
-	if (!of_mutex_lock(&mutex))
+	if (of_mutex_lock(&mutex) != 0)
 		OBJC_ERROR("Failed to lock mutex!");
 
 	/* Look if we already have a lock */
 	for (lock = locks; lock != NULL; lock = lock->next) {
 		if (lock->object != object)
 			continue;
 
 		lock->count++;
 
-		if (!of_mutex_unlock(&mutex))
+		if (of_mutex_unlock(&mutex) != 0)
 			OBJC_ERROR("Failed to unlock mutex!");
 
-		if (!of_rmutex_lock(&lock->rmutex))
+		if (of_rmutex_lock(&lock->rmutex) != 0)
 			OBJC_ERROR("Failed to lock mutex!");
 
 		return 0;
 	}
 
 	/* Create a new lock */
 	if ((lock = malloc(sizeof(*lock))) == NULL)
 		OBJC_ERROR("Failed to allocate memory for mutex!");
 
-	if (!of_rmutex_new(&lock->rmutex))
+	if (of_rmutex_new(&lock->rmutex) != 0)
 		OBJC_ERROR("Failed to create mutex!");
 
 	lock->object = object;
 	lock->count = 1;
 	lock->next = locks;
 
 	locks = lock;
 
-	if (!of_mutex_unlock(&mutex))
+	if (of_mutex_unlock(&mutex) != 0)
 		OBJC_ERROR("Failed to unlock mutex!");
 
-	if (!of_rmutex_lock(&lock->rmutex))
+	if (of_rmutex_lock(&lock->rmutex) != 0)
 		OBJC_ERROR("Failed to lock mutex!");
 #endif
 
 	return 0;
 }
@@ -100,24 +100,24 @@
 		return 0;
 
 #ifdef OF_HAVE_THREADS
 	struct lock_s *lock, *last = NULL;
 
-	if (!of_mutex_lock(&mutex))
+	if (of_mutex_lock(&mutex) != 0)
 		OBJC_ERROR("Failed to lock mutex!");
 
 	for (lock = locks; lock != NULL; lock = lock->next) {
 		if (lock->object != object) {
 			last = lock;
 			continue;
 		}
 
-		if (!of_rmutex_unlock(&lock->rmutex))
+		if (of_rmutex_unlock(&lock->rmutex) != 0)
 			OBJC_ERROR("Failed to unlock mutex!");
 
 		if (--lock->count == 0) {
-			if (!of_rmutex_free(&lock->rmutex))
+			if (of_rmutex_free(&lock->rmutex) != 0)
 				OBJC_ERROR("Failed to destroy mutex!");
 
 			if (last != NULL)
 				last->next = lock->next;
 			if (locks == lock)
@@ -124,11 +124,11 @@
 				locks = lock->next;
 
 			free(lock);
 		}
 
-		if (!of_mutex_unlock(&mutex))
+		if (of_mutex_unlock(&mutex) != 0)
 			OBJC_ERROR("Failed to unlock mutex!");
 
 		return 0;
 	}