groostav
04/28/2017, 6:55 PMReadFileEx
states this:
Reads data from the specified file or input/output (I/O) device. It reports its completion status asynchronously, calling the specified completion routine when reading is completed or canceled and the calling thread is in an alertable wait state.Digging up what that means:
An application-defined callback function used with the ReadFileEx and WriteFileEx functions. It is called when the asynchronous input and output (I/O) operation is completed or canceled and the calling thread is in an alertable state (by using the SleepEx, MsgWaitForMultipleObjectsEx, WaitForSingleObjectEx, or WaitForMultipleObjectsEx function with the fAlertable parameter set to TRUE).