@@ -14,10 +14,14 @@
  * file.
  */
 
 #import "OFThread.h"
 
+OF_ASSUME_NONNULL_BEGIN
+
 #ifdef OF_HAVE_THREADS
 @interface OFThread (OF_PRIVATE_CATEGORY)
 + (void)OF_createMainThread;
 @end
 #endif
+
+OF_ASSUME_NONNULL_END