A lovely trick I found with libdispatch: when the async-nature is specified dynamically, invoke via a function pointer determined by the ternary operator:

A lovely trick I found with libdispatch: when the async-nature is specified dynamically, invoke via a function pointer determined by the ternary operator: (async ? dispatch_async : dispatch_sync)(queue, ^{ /* stuff */ }); The reader does a double-take, but it's so damn pretty!