October 12th, 2005

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

Raymond Chen
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 while another is busy displaying it, for example. (More on this subject later.)

Icons, cursors, and accelerator tables behave like menus. They do not have thread affinity. They are easier to manage than menus since they cannot be modified once created, so the only thing you have to worry about is not to use one after it has been destroyed.

Next time, GDI objects and an expansion on the subject of thread safety.

Category
Old New Thing
Topics
Code

Author

Raymond Chen

Raymond has been involved in the evolution of Windows for more than 30 years. In 2003, he began a Web site known as The Old New Thing which has grown in popularity far beyond his wildest imagination, a development which still gives him the heebie-jeebies. The Web site spawned a book, coincidentally also titled The Old New Thing (Addison Wesley 2007). He occasionally appears on the Windows Dev Docs Twitter account to tell stories which convey no useful information.

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