@@ -15,12 +15,10 @@
 
 #include "objfw-defs.h"
 
 #import "macros.h"
 
-/** @file */
-
 #if defined(OF_HAVE_PTHREADS)
 # include <pthread.h>
 typedef pthread_once_t OFOnceControl;
 # define OFOnceControlInitValue PTHREAD_ONCE_INIT
 #elif defined(OF_HAVE_ATOMIC_OPS)
@@ -29,11 +27,13 @@
 #elif defined(OF_AMIGAOS) || !defined(OF_HAVE_THREADS)
 typedef int OFOnceControl;
 # define OFOnceControlInitValue 0
 #endif
 
-typedef void (*OFOnceFunction)(void);
+OF_ASSUME_NONNULL_BEGIN
+
+/** @file */
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 /**
@@ -46,5 +46,7 @@
  */
 extern void OFOnce(OFOnceControl *control, void (*function)(void));
 #ifdef __cplusplus
 }
 #endif
+
+OF_ASSUME_NONNULL_END