Thread overview
How can execute method in new Thread?
Nov 14
Marcone
Nov 15
frame
November 14
My simple example code:

import std;

struct Fruit {
	string name;
	this(string name){
		this.name = name;
	}

	void printmyname(){
		writeln(this.name);
	}

	void showname(){
		task!this.printmyname().executeInNewThread(); // Error here!! Can not send this.printmyname() tonew thread.
	}
}


void main(){
	Fruit f = Fruit("Banana");
	f.showname();
}


Error: D:\dmd2\windows\bin\..\..\src\phobos\std\parallelism.d(516): Error: struct `Fruit` does not overload ()
November 15
On Saturday, 14 November 2020 at 17:21:15 UTC, Marcone wrote:

> Error: D:\dmd2\windows\bin\..\..\src\phobos\std\parallelism.d(516): Error: struct `Fruit` does not overload ()

You can't. Because everything that can run in a new thread must be a (separate) function. If you are using an object (you accessing this) the compiler will generate a delegate instead and cannot pass that to a thread.

So you need to make printmyname() a static function. Then you have the problem that you cannot access the object (this). You can only pass the instance you want to work with as a function argument.

You do not need "ref" here. But if you omit that keyword the struct may get copied instead and you will see no changes in the passed struct.

struct Fruit {
    string name;

    this(string name){
        this.name = name;
    }

    static void printmyname(ref Fruit fruit){
        writeln(fruit.name);
    }

    void showname(){
        task!(printmyname)(this).executeInNewThread();
    }
}


November 15
On Saturday, 14 November 2020 at 17:21:15 UTC, Marcone wrote:
> Error: D:\dmd2\windows\bin\..\..\src\phobos\std\parallelism.d(516): Error: struct `Fruit` does not overload ()

I think you need to pass the this pointer somehow. This works:


import std;

struct Fruit {
    string name;

    static void printmyname(Fruit thisFruit)
    {
        writeln(thisFruit.name);
    }

    void showname()
    {
         task!printmyname(this).executeInNewThread;
    }
}


void main()
{
    Fruit f = Fruit("Banana");
    f.showname();
}


This does too:


import std;

struct Fruit
{
    string name;

    void printmyname()
    {
        writeln(name);
    }

    void showname()
    {
        task!((Fruit me){me.printmyname;})(this).executeInNewThread;
    }
}


void main()
{
    Fruit f = Fruit("Banana");
    f.showname();
}


—Bastiaan.