A callback function is a function that you write that could be called by outside code (i.e. by windows functions). You set up a callback function by passing the address of your function to the API from which your callback is referenced.<br><br>For example, I want my application to handle runtime exceptions rather than letting C++ runtime take care of things for me. So I wrote a function called my_exception_handler(int, EXCEPTION_POINTERS*) and I call a Microsoft function called _set_se_translator and pass it the address of my_exception_handler. <br><br>In the example above, my_exception_handler is a callback function -- I will never call it myself, but I pass the address of it to an API that will cause it to possibly be called.<br><br>Hope that helps!<br><br> <p>Pat Gleason<br><a href=mailto:gleason@megsinet.net>gleason@megsinet.net</a><br><a href= > </a><br>