A proxy is a form of non-blocking message especially suited for event notification where the sending process does not need to interact with the recipient. The only function of a proxy is to send a fixed message to a specific process that owns the proxy. Like messages, proxies work across the network. By using a proxy, a process or an interrupt handler can send a message to another process without blocking or having to wait for a reply.
Proxies are created with the qnx_proxy_attach() C function. Any other process or any interrupt handler that knows the identification of the proxy can then cause the proxy to deliver its predefined message by using the Trigger() C function. The Kernel handles the Trigger() request. A proxy can be triggered more than once -it sends a message for each time it's triggered. A proxy process can queue up to 65,535 messages for delivery.