@@ -47,19 +47,19 @@
 /**
  * \brief Creates a new Thread Local Storage key
  *
  * \return A new, autoreleased Thread Local Storage key
  */
-+ TLSKey;
++ (instancetype)TLSKey;
 
 /**
  * \brief Creates a new Thread Local Storage key with the specified destructor.
  *
  * \param destructor A destructor that is called when the thread is terminated
  * \return A new autoreleased Thread Local Storage key
  */
-+ TLSKeyWithDestructor: (void(*)(id))destructor;
++ (instancetype)TLSKeyWithDestructor: (void(*)(id))destructor;
 
 + (void)callAllDestructors;
 
 /**
  * \brief Initializes an already allocated Thread Local Storage Key with the
@@ -111,28 +111,28 @@
 /**
  * \brief Creates a new thread.
  *
  * \return A new, autoreleased thread
  */
-+ thread;
++ (instancetype)thread;
 
 /**
  * \brief Creates a new thread with the specified object.
  *
  * \param object An object which is passed for use in the main method or nil
  * \return A new, autoreleased thread
  */
-+ threadWithObject: (id)object;
++ (instancetype)threadWithObject: (id)object;
 
 #ifdef OF_HAVE_BLOCKS
 /**
  * \brief Creates a new thread with the specified block.
  *
  * \param block A block which is executed by the thread
  * \return A new, autoreleased thread
  */
-+ threadWithBlock: (of_thread_block_t)block;
++ (instancetype)threadWithBlock: (of_thread_block_t)block;
 #endif
 
 /**
  * \brief Sets the Thread Local Storage for the specified key.
  *
@@ -273,11 +273,11 @@
 /**
  * \brief Creates a new mutex.
  *
  * \return A new autoreleased mutex.
  */
-+ mutex;
++ (instancetype)mutex;
 
 /**
  * \brief Locks the mutex.
  */
 - (void)lock;
@@ -317,11 +317,11 @@
 /**
  * \brief Creates a new condition.
  *
  * \return A new, autoreleased OFCondition
  */
-+ condition;
++ (instancetype)condition;
 
 /**
  * \brief Blocks the current thread until another thread calls -[signal] or
  *	  -[broadcast].
  */