ZeroMQ

Delivery Notifications

One of the nice things about the multithreaded API model we’re using is that it’s essentially message-based. This makes it ideal for returning events back to the caller. A more conventional API approach would be to use callbacks, but callbacks that cross thread boundaries are somewhat delicate. Here’s how the client sends a message back when it has received a complete file:

zstr_sendm (self->pipe, "DELIVER");
zstr_sendm (self->pipe, filename);
zstr_sendf (self->pipe, "%s/%s", inbox, filename);

We can now add a _recv() method to the API that waits for events back from the client. It makes a clean style for the caller: create the client object, configure it, and then receive and process any events it returns.