@@ -14,10 +14,12 @@
  * file.
  */
 
 #import "OFException.h"
 
+OF_ASSUME_NONNULL_BEGIN
+
 /*!
  * @class OFOpenItemFailedException \
  *	  OFOpenItemFailedException.h ObjFW/OFOpenItemFailedException.h
  *
  * @brief An exception indicating an item could not be opened.
@@ -34,11 +36,11 @@
 @property (readonly, nonatomic) OFString *path;
 
 /*!
  * The mode in which the item should have been opened.
  */
-@property (readonly, nonatomic) OFString *mode;
+@property OF_NULLABLE_PROPERTY (readonly, nonatomic) OFString *mode;
 
 /*!
  * The errno of the error that occurred.
  */
 @property (readonly) int errNo;
@@ -57,11 +59,11 @@
  * @param path A string with the path of the item tried to open
  * @param mode A string with the mode in which the item should have been opened
  * @return A new, autoreleased open item failed exception
  */
 + (instancetype)exceptionWithPath: (OFString*)path
-			     mode: (OFString*)mode;
+			     mode: (nullable OFString*)mode;
 
 /*!
  * @brief Creates a new, autoreleased open item failed exception.
  *
  * @param path A string with the path of the item tried to open
@@ -78,11 +80,11 @@
  * @param mode A string with the mode in which the item should have been opened
  * @param errNo The errno of the error that occurred
  * @return A new, autoreleased open item failed exception
  */
 + (instancetype)exceptionWithPath: (OFString*)path
-			     mode: (OFString*)mode
+			     mode: (nullable OFString*)mode
 			    errNo: (int)errNo;
 
 /*!
  * @brief Initializes an already allocated open item failed exception.
  *
@@ -97,11 +99,11 @@
  * @param path A string with the path of the item which could not be opened
  * @param mode A string with the mode in which the item should have been opened
  * @return An initialized open item failed exception
  */
 - initWithPath: (OFString*)path
-	  mode: (OFString*)mode;
+	  mode: (nullable OFString*)mode;
 
 /*!
  * @brief Initializes an already allocated open item failed exception.
  *
  * @param path A string with the path of the item which could not be opened
@@ -118,8 +120,10 @@
  * @param mode A string with the mode in which the item should have been opened
  * @param errNo The errno of the error that occurred
  * @return An initialized open item failed exception
  */
 - initWithPath: (OFString*)path
-	  mode: (OFString*)mode
+	  mode: (nullable OFString*)mode
 	 errNo: (int)errNo;
 @end
+
+OF_ASSUME_NONNULL_END