Thread affinity of user interface objects, part 5: Object clean-up

October 14, 2005 Oct 14, 2005 10/14/05

Raymond Chen

The window manager and GDI objects as a general rule will automatically destroy objects created by a process when that process terminates. (The window manager also destroys windows when their owner threads exit.) Note, however, that this is a safety net and not an excuse for you to leak resources in your own program with the attitude of "Oh, ...

Thread affinity of user interface objects, part 4: GDI objects and other notes on affinity

October 13, 2005 Oct 13, 2005 10/13/05

Raymond Chen

GDI objects are much simpler. As a general rule, they all have process affinity: They can be used by any thread in the process that created them. If you use a GDI object from multiple threads, it is your responsibility to coordinate the object's use. Note that the window manager and GDI as a general rule keep their respective objects thread-...

Thread affinity of user interface objects, part 3: Menus, icons, cursors, and accelerator tables

October 12, 2005 Oct 12, 2005 10/12/05

Raymond Chen

The remaining user interface objects in common use are menus, icons, cursors, and accelerator tables. Menus do not have thread affinity. Any thread can use a menu. However, if two threads use a menu, it is the responsibility of those threads to coordinate among themselves how that menu will be used, so that one thread doesn't modify a menu ...

Thread affinity of user interface objects, part 2: Device contexts

October 11, 2005 Oct 11, 2005 10/11/05

Raymond Chen

Last time, we discussed briefly the thread affinity rules that govern window handles. Device contexts (DCs) also have a certain degree of thread affinity. The thread that calls functions such as GetDC must also be the one that calls ReleaseDC, but as with window handles, during the lifetime of the DC, any thread can use it. If you choose ...

Thread affinity of user interface objects, part 1: Window handles

October 10, 2005 Oct 10, 2005 10/10/05

Raymond Chen

Different objects have different thread affinity rules, but the underlying principles come from 16-bit Windows. The most important user interface element is of course the window. Window objects have thread affinity. The thread that creates a window is the one with which the window has an inseparable relationship. Informally, one says that ...