@@ -34,20 +34,20 @@
 #endif
 static of_tlskey_t threadKey;
 
 OF_CONSTRUCTOR()
 {
-	OF_ENSURE(of_tlskey_new(&threadKey));
+	OF_ENSURE(of_tlskey_new(&threadKey) == 0);
 }
 
 static void
 functionWrapper(void)
 {
 	bool detached = false;
 	of_thread_t thread =
 	    (of_thread_t)((struct Process *)FindTask(NULL))->pr_ExitData;
-	OF_ENSURE(of_tlskey_set(threadKey, thread));
+	OF_ENSURE(of_tlskey_set(threadKey, thread) == 0);
 
 	thread->function(thread->object);
 
 	ObtainSemaphore(&thread->semaphore);
 	@try {
@@ -67,29 +67,27 @@
 
 	if (detached)
 		free(thread);
 }
 
-bool
+int
 of_thread_attr_init(of_thread_attr_t *attr)
 {
 	attr->priority = 0;
 	attr->stackSize = 0;
 
-	return true;
+	return 0;
 }
 
-bool
+int
 of_thread_new(of_thread_t *thread, const char *name, void (*function)(id),
     id object, const of_thread_attr_t *attr)
 {
 	OFMutableData *tags = nil;
 
-	if ((*thread = calloc(1, sizeof(**thread))) == NULL) {
-		errno = ENOMEM;
-		return false;
-	}
+	if ((*thread = calloc(1, sizeof(**thread))) == NULL)
+		return ENOMEM;
 
 	@try {
 		(*thread)->function = function;
 		(*thread)->object = object;
 		InitSemaphore(&(*thread)->semaphore);
@@ -122,14 +120,12 @@
 		ADD_TAG(NP_CloseInput, FALSE)
 		ADD_TAG(NP_CloseOutput, FALSE)
 		ADD_TAG(NP_CloseError, FALSE)
 
 		if (attr != NULL && attr->priority != 0) {
-			if (attr->priority < 1 || attr->priority > 1) {
-				errno = EINVAL;
-				return false;
-			}
+			if (attr->priority < 1 || attr->priority > 1)
+				return EINVAL;
 
 			/*
 			 * -1 should be -128 (lowest possible priority) while
 			 * +1 should be +127 (highest possible priority).
 			 */
@@ -147,51 +143,46 @@
 #undef ADD_TAG
 
 		(*thread)->task = (struct Task *)CreateNewProc(tags.items);
 		if ((*thread)->task == NULL) {
 			free(*thread);
-			errno = EAGAIN;
-			return false;
+			return EAGAIN;
 		}
 	} @catch (id e) {
 		free(*thread);
 		@throw e;
 	} @finally {
 		[tags release];
 	}
 
-	return true;
+	return 0;
 }
 
 of_thread_t
 of_thread_current(void)
 {
 	return of_tlskey_get(threadKey);
 }
 
-bool
+int
 of_thread_join(of_thread_t thread)
 {
 	ObtainSemaphore(&thread->semaphore);
 
 	if (thread->done) {
 		ReleaseSemaphore(&thread->semaphore);
 
 		free(thread);
-		return true;
+		return 0;
 	}
 
 	@try {
-		if (thread->detached || thread->joinTask != NULL) {
-			errno = EINVAL;
-			return false;
-		}
-
-		if ((thread->joinSigBit = AllocSignal(-1)) == -1) {
-			errno = EAGAIN;
-			return false;
-		}
+		if (thread->detached || thread->joinTask != NULL)
+			return EINVAL;
+
+		if ((thread->joinSigBit = AllocSignal(-1)) == -1)
+			return EAGAIN;
 
 		thread->joinTask = FindTask(NULL);
 	} @finally {
 		ReleaseSemaphore(&thread->semaphore);
 	}
@@ -200,14 +191,14 @@
 	FreeSignal(thread->joinSigBit);
 
 	assert(thread->done);
 	free(thread);
 
-	return true;
+	return 0;
 }
 
-bool
+int
 of_thread_detach(of_thread_t thread)
 {
 	ObtainSemaphore(&thread->semaphore);
 
 	if (thread->done)
@@ -215,12 +206,12 @@
 	else
 		thread->detached = true;
 
 	ReleaseSemaphore(&thread->semaphore);
 
-	return true;
+	return 0;
 }
 
 void
 of_thread_set_name(const char *name)
 {
 }