How to pass arguments to a thread?

1

Hi there!

This is my code at the moment:

Thread.create( my_function );

I would like to pass some parameters upon creating the thread. However Thread.create only accepts an input of

() -> Void

so it seems I cannot pass any values to the thread. But I need something like this instead:

( a : MyClass ) -> Void

Or even any values.

Solutions (?)

  • Must I override the Thread.create field/method in a custom Thread class?
  • Do I need Thread.sendMessage and .readMessage for that?
  • Also this won’t work obivously:
Thread.create( my_function( a, b ) );

Let me know what you think.
Thank you.

2 
	var mystr = "Hello";
	var myfunc = () -> { trace(mystr); }

	Thread.runWithEventLoop( myfunc );
3

Alternatively:

Thread.create(my_function.bind(a,b))
1 Like
4

That will not work because bind requires function taking array as an argument, while callback is of (Void)->Void type

Main.hx:: characters 2-13 : Too many callback arguments
5

Hi, thank you for your ideas!!

So in my case it seems the .bind() thing works with both the class method as well as with a local arrow function:

class Threads {
        static function main() {

                // uses method
                Thread.create( threadAcceptingArguments.bind("hi!") );

                Sys.sleep( 0.5 );

                // uses local arrow function
                var j = ( n:Int ) -> { trace( 'n=$n' ); };
                Thread.create( j.bind(10901) );

                Sys.sleep( 0.5 );
        }

        static function threadAcceptingArguments( string:String ) {
                trace( string );
        }
}

Output:

src/Threads.hx:5: hi!
src/Threads.hx:10: n=10901

I think this is still impressive that Thread.create( job:()->Void ) does accept “bind arguments” for job… I heard of bindings before, but now I’m glad they exist I guess.

edit: Maybe I should also say I only tried this with HashLink (!), maybe it won’t work on all platforms the same way (?)

6

Bind just creates closures around functions, i.e. it just does what you suggested but with simpler syntax.

Perhaps bind expects an array on a specific platform?

7

It was my mistake; I called bind on function without arguments, glad it works.

1 Like