Synchronized as a keyword and property is not available
Edit me

Use mulle-thread for least hassle.

mulle-thread is available on all platforms, that run Objective-C.

Use mulle_thread_mutex_t to transform

- (void) myFunction
{
   @synchronized()
   {
   }
}

to

static mulle_thread_mutex_t   lock;


+ (void) load
{
   mulle_thread_mutex_init( &lock);
}


- (void) myFunction
{
   mulle_thread_mutex_lock( &lock);
   {

   }
   mulle_thread_mutex_unlock( &lock);
}

Use NSLock instead

static NSLock   lock;


+ (void) initialize
{
   if( ! lock)
      lock = [[NSLock alloc] init];
}

+ (void) deinitialize
{
   if( lock)
   {
      [lock release];
      lock = nil;
   }
}


- (void) myFunction
{
   [lock lock];
   {

   }
   [lock unlock];
}

Good points

  • code works in all runtimes without another dependency
  • +deinitialize will not be called by other runtimes, it’s a harmless addition

Bad points

  • A NSLock is slower than a mulle_thread_mutex_t
  • The lock has not become a proper MulleObjC root object, so this code will leak in tests.

You could fix this with deleting +deinitialize and rewriting +initialize as:

+ (void) initialize
{
   if( ! lock)
   {
      lock = [[NSLock alloc] init];
#ifdef __MULLE_OBJC__
      [lock _becomeRootObject];
      [lock release;]
#endif
   }
}

// + (void) deinitialize clashes with  _becomeRootObject and must be removed