@@ -14,10 +14,12 @@
  * file.
  */
 
 #import "OFMutex.h"
 
+OF_ASSUME_NONNULL_BEGIN
+
 @class OFDate;
 
 /*!
  * @class OFCondition OFCondition.h ObjFW/OFCondition.h
  *
@@ -68,5 +70,7 @@
 /*!
  * @brief Signals all threads to continue.
  */
 - (void)broadcast;
 @end
+
+OF_ASSUME_NONNULL_END