GCD usage example.

samples/objc/src/main/kotlin/Window.kt

@@ -3,6 +3,8 @@ import platform.AppKit.*
 import platform.Foundation.*
 import platform.objc.*
 import platform.osx.*
+import platform.darwin.*
+import platform.posix.*
 
 fun main(args: Array<String>) {
     autoreleasepool {
@@ -20,9 +22,29 @@ private fun runApp() {
     app.run()
 }
 
+data class Data(val stamp: Long)
+
+private class Controller : NSObject() {
+    private val asyncQueue = dispatch_queue_create("com.jetbrains.CustomQueue", null)
+
+    @ObjCAction
+    fun onClick() {
+        // Execute some async action on button click.
+        dispatch_async_f(asyncQueue, konan.worker.detachObjectGraph {
+            Data(clock_gettime_nsec_np(CLOCK_REALTIME))
+        }, staticCFunction {
+            it ->
+            initRuntimeIfNeeded()
+            val data = konan.worker.attachObjectGraph<Data>(it)
+            println("in async: $data")
+        })
+    }
+}
+
 private class MyAppDelegate() : NSObject(), NSApplicationDelegateProtocol {
 
     private val window: NSWindow
+    private val controller = Controller()
 
     init {
         val mainDisplayRect = NSScreen.mainScreen()!!.frame
@@ -33,6 +55,7 @@ private class MyAppDelegate() : NSObject(), NSApplicationDelegateProtocol {
                     size.width * 0.5,
                     size.height * 0.5
             )
+
         }
 
         val windowStyle = NSWindowStyleMaskTitled or NSWindowStyleMaskMiniaturizable or
@@ -54,6 +77,13 @@ private class MyAppDelegate() : NSObject(), NSApplicationDelegateProtocol {
                 }
             }
         }
+
+        val button = NSButton().initWithFrame(NSMakeRect(10.0, 10.0, 100.0, 40.0)).apply {
+            title = "Press me"
+            target = controller
+            action = NSSelectorFromString("onClick")
+        }
+        window.contentView!!.addSubview(button)
     }
 
     override fun applicationWillFinishLaunching(notification: NSNotification) {