The Old New Thing

The alertable wait is the non-GUI analog to pumping messages

May 3, 2006 May 3, 2006 05/3/06

Raymond Chen

When you are doing GUI programming, you well know thatthe message pump is the primary way of receiving and dispatchingmessages.The non-GUI analog to the message pump is the alertable wait.A user-mode APC is a request for a function to run on a threadin user mode.You can explicitly queue an APC to a thread with theQueueUserAPC ...

A cache with a bad policy is another name for a memory leak

May 2, 2006 May 2, 2006 05/2/06

Raymond Chen

A common performance trick is to reduce time spent in the heap managerby caching the last item freed (or maybe the last few)so that a subsequent allocation can just re-use the item ratherthan having to go make a new one.But you need to be careful how you do this or you can end upmaking things worse rather than better.Here's an example ...

What's so special about bitmaps and DCs?

May 1, 2006 May 1, 2006 05/1/06

Raymond Chen

You can select pens, brushes, fonts and bitmaps into a DC with the SelectObject function, and from this list, bitmaps are special. Because, if you look carefully, bitmaps are the only modifiable objects on the list. Pens, brushes and fonts cannot be modified once they are created. But bitmaps, oh, bitmaps. A bitmap selected into a DC changes ...