Help with Concurrency

[Nicholas Wilson via Digitalmars-d-learn]

On Tuesday, 3 November 2015 at 23:16:59 UTC, bertg wrote:
> I am having trouble with a simple use of concurrency.
>
> Running the following code I get 3 different tid's, multiple 
> "sock in" messages printed, but no receives. I am supposed to 
> get a "received!" for each "sock in", but I am getting hung up 
> on "receiving...".
>
> Am I misusing or misunderstanding the use of mailboxes?
>
> ===
>
> class Connection {
>     Reactor reactor;
>     WebSocket webSocket;
>
>     this(Reactor r, WebSocket ws)
>     {
>         reactor = r;
>         webSocket = ws;
>
>         messageLoop();
>     }
>
>     void messageLoop()
>     {
>         std.concurrency.Tid tid = std.concurrency.thisTid();
>         writeln("tid 1 ~ " ~ 
> to!string(std.concurrency.thisTid()));
>         writeln("tid 2 ~ " ~ 
> to!string(std.concurrency.thisTid()));
>         writeln("tid 3 ~ " ~ 
> to!string(std.concurrency.thisTid()));
>
>         // deal with websocket messages
>         spawn(&handleConnectionWebSocket, tid, cast(shared) 
> webSocket);
>         // deal with pub/sub
>         //spawn();
>
Try replacing the following loop to have a receive that times out 
or while(true) to while(web socked.connected)
>         while (true) {
>             writeln("receiving...");
>             std.concurrency.receive(
>                 (string msg) {
>                     writeln("conn: received ws message: " ~ 
> msg);
>                 }
>             );
>             writeln("received!");
>         }
>     }
> }
> void handleConnectionWebSocket(std.concurrency.Tid caller, 
> shared WebSocket ws)
> {
>     auto sock = cast(WebSocket) ws;
>     while (sock.connected) {
>         writeln("sock in");
>         auto msgIn = sock.receiveText();
>         std.concurrency.send(caller, msgIn);
>     }
> }