A function designator.
wait-reason provides the value returned by process-whostate when called on the current process.
wait-function is called periodically with arguments wait-args . wait-function may be called many times and in several places. Therefore wait-function should be fast and make no assumptions about its dynamic context.
processes all events sent to the current process, including system events such as window messages on MS Windows, and events sent by other processes via process-send. It is a useful alternative to
in a situation where you want to process events to see window updates and so on.