asynchronous procedure call (APC)

A function that executes asynchronously in the context of a particular thread. When an APC is queued to a thread, the system issues a software interrupt. The next time the thread is scheduled, it will run the APC. APCs made by the system are called "kernel-mode APCs." APCs made by an application are called "user-mode APCs." A thread must be in an alertable state to run a user-mode APC.