@@ -121,21 +121,21 @@
 # endif
 
 			numPreallocatedPages--;
 # if !defined(OF_HAVE_COMPILER_TLS) && defined(OF_HAVE_THREADS)
 			OF_ENSURE(of_tlskey_set(numPreallocatedPagesKey,
-			    (void *)numPreallocatedPages));
+			    (void *)numPreallocatedPages) == 0);
 # endif
 
 			page = preallocatedPages[numPreallocatedPages];
 
 			if (numPreallocatedPages == 0) {
 				free(preallocatedPages);
 				preallocatedPages = NULL;
 # if !defined(OF_HAVE_COMPILER_TLS) && defined(OF_HAVE_THREADS)
 				OF_ENSURE(of_tlskey_set(preallocatedPagesKey,
-				    preallocatedPages));
+				    preallocatedPages) == 0);
 # endif
 			}
 
 			return page;
 		}
@@ -171,14 +171,14 @@
 	lastPage = page;
 
 	if (firstPage == NULL)
 		firstPage = page;
 # else
-	OF_ENSURE(of_tlskey_set(lastPageKey, page));
+	OF_ENSURE(of_tlskey_set(lastPageKey, page) == 0);
 
 	if (of_tlskey_get(firstPageKey) == NULL)
-		OF_ENSURE(of_tlskey_set(firstPageKey, page));
+		OF_ENSURE(of_tlskey_set(firstPageKey, page) == 0);
 # endif
 
 	return page;
 }
 
@@ -207,13 +207,13 @@
 		firstPage = page->next;
 	if (lastPage == page)
 		lastPage = page->previous;
 # else
 	if (of_tlskey_get(firstPageKey) == page)
-		OF_ENSURE(of_tlskey_set(firstPageKey, page->next));
+		OF_ENSURE(of_tlskey_set(firstPageKey, page->next) == 0);
 	if (of_tlskey_get(lastPageKey) == page)
-		OF_ENSURE(of_tlskey_set(lastPageKey, page->previous));
+		OF_ENSURE(of_tlskey_set(lastPageKey, page->previous) == 0);
 # endif
 
 	free(page);
 }
 
@@ -272,13 +272,14 @@
 + (void)initialize
 {
 	if (self != [OFSecureData class])
 		return;
 
-	if (!of_tlskey_new(&firstPageKey) || !of_tlskey_new(&lastPageKey) ||
-	    !of_tlskey_new(&preallocatedPagesKey) ||
-	    !of_tlskey_new(&numPreallocatedPagesKey))
+	if (of_tlskey_new(&firstPageKey) != 0 ||
+	    of_tlskey_new(&lastPageKey) != 0 ||
+	    of_tlskey_new(&preallocatedPagesKey) != 0 ||
+	    of_tlskey_new(&numPreallocatedPagesKey) != 0)
 		@throw [OFInitializationFailedException
 		    exceptionWithClass: self];
 }
 #endif
 
@@ -296,11 +297,11 @@
 	if (preallocatedPages != NULL)
 		@throw [OFInvalidArgumentException exception];
 
 	preallocatedPages = of_alloc_zeroed(numPages, sizeof(struct page));
 # if !defined(OF_HAVE_COMPILER_TLS) && defined(OF_HAVE_THREADS)
-	of_tlskey_set(preallocatedPagesKey, preallocatedPages);
+	OF_ENSURE(of_tlskey_set(preallocatedPagesKey, preallocatedPages) == 0);
 # endif
 
 	@try {
 		for (i = 0; i < numPages; i++)
 			preallocatedPages[i] = addPage(false);
@@ -314,12 +315,12 @@
 		@throw e;
 	}
 
 	numPreallocatedPages = numPages;
 # if !defined(OF_HAVE_COMPILER_TLS) && defined(OF_HAVE_THREADS)
-	of_tlskey_set(numPreallocatedPagesKey,
-	    (void *)(uintptr_t)numPreallocatedPages);
+	OF_ENSURE(of_tlskey_set(numPreallocatedPagesKey,
+	    (void *)(uintptr_t)numPreallocatedPages) == 0);
 # endif
 #else
 	@throw [OFNotImplementedException exceptionWithSelector: _cmd
 							 object: self];
 #endif