Month Three : Week Two
This week the main issue I ran into was dealing with the X11 window event system. The event loop is running on its own thread so it is hard to tell when a window call is going to be processed and have the changes made be visible to the user. This meant that an X11 function may be called successfully, but the Test-Suite would keep moving on to the next test before the function was completed, making the test-suite get off track and start failing.
Like most operating systems, when an X11 event is sent it enters a queue that processes messages one by one until the queue is empty. For the purposes of my library, I need the results of the functions I call to be in effect before the program continues on. Because this was not occurring I was experiencing very frustrating bugs that were not immediately obvious. For instance, when minimizing or moving a window or messing with its borders, the window would not react for several seconds but the function would return true because the action was successful, it just wasn't visible yet.
By looking through some example code of other window handlers it became apparent that most X11 calls could be followed by XFlush() which will flush and process every message in the queue. By adding an XFlush() and sleep(1) after every X11 call that edits a window I was able to make sure that the functions were completing and actually changing the window before my program is allowed to move on, which resulted in successful tests.
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