How do I force something onto the heap? (need for libev)

[Mike Parker]

On 3/6/2012 1:55 PM, Mike Parker wrote:
> On 3/6/2012 1:34 PM, Tyler Jameson Little wrote:
>> I've been playing with libev in D lately, and I've run into a problem.
>> I've been able to hack around it, but it'd like to find a better, more
>> general solution. Here's a link to the code:
>>
>> https://github.com/beatgammit/fun-with-d/blob/master/libev/tcp_server.d
>>
>> The code is a basic TCP server that responds to connections in a
>> non-blocking fashion. It's not perfect, and the current problem I'm
>> trying to solve is how to get my Socket instance (from accept) to the
>> handler. Since everything is asynchronous, and the return value of
>> accept() will get lost (garbage collected, I think). When I try to get
>> the address of it, the compiler complains that it's not an lvalue.
>
> Socket instance returned by accept won't be garbage collected (or lost)
> as long as you have a reference to it active somewhere in your program.
> It doesn't matter which thread. Just take the return value of accept and
> pass it to your handler as is. As long as your handler holds on to the
> reference, you're fine. No need to try and get the address, or hack
> around it.

Ah, sorry. Never mind. I misunderstood the problem.

I suggest you keep an associative array of Sockets, using req.handle as 
a key. Then, your code becomes this:

// The map
Socket[socket_t] sockets;

// in connection_cb
auto req = server.accept();
sockets[req.handle] = req;

// then in socket_watcher_cb
auto req = sockets[w.fd];