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Re: MT opens up whole new can of worms :) [message #46160 is a reply to message #46144]

Mon, 21 March 2016 10:41

cbpporter
Messages: 1401
Registered: September 2007

Ultimate Contributor

Well, I do all the GUI stuff on the main thread.

Still, after years of experience with GUI, you get a very good feel of when and why events should trigger and you learn to write short code that best uses these rules.

With MT, events trigger all around in non deterministic orders and the only good solution I found is to turn some off while background threads are running and turn them back on once they are done, combined with a ticketing system, so that the event can't be triggered only if the tickets match.

One rather simple example is editing code vs. updating a code navigator. If you do it with ST, once the code analysis is done, the navigator can be updated, which will sometimes resolve in an order change of items and the cursor position must be changed. So an event will be triggered and the cursor in the editor changed, but this is not a problem since the cursor is restored after the navigation update procedure. With MT, if the cursor changes due to a thread, events shouldn't trigger since that makes the editor incapable of doing mouse select, but if you click on it, it should work.

The rest of the cases are more complicated than this.

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