What does the term "input-synchronized calls" mean?

Question

I found this in an article on Multithreaded Apartments, but can’t find a definition for “input-synchronized calls”. (Article is at http://msdn.microsoft.com/en-us/library/ms693421(VS.85).aspx)

As used in the article - Multithreaded apartments cannot make input-synchronized calls

What are “input-synchronized" calls?

Thanks

Answer 1

Have a look at this article here.

Input-synchronized calls - When making input-synchronized calls, the object called must complete the call before yielding control. This helps ensure that focus management works correctly and that data entered by the user is processed appropriately. These calls are made by COM through the Windows SendMessage function, without entering a modal loop. While processing an input-synchronized call, the object called must not call any function or method (including synchronous methods) that might yield control.