This configuration variable tells the Windows runtime to automatically call the Windows PeekMessage() API function between file operations. When the FILE_IO_PEEKS_MESSAGES configuration variable is set to 1 (on, true, yes), the runtime calls PeekMessage() with flags that tell it to simply check for messages without removing them from the message queue. This operation tells Windows that the application is alive and responding. The default value of the variable is 0 (off, false, no).