Re: Thread synchronisation

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#13676

From: Remy Lebeau (TeamB)
Date: Sat, 27 Sep 2003 04:00

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"Wim Bekker" <wim@bekker> wrote in message
news:3f704989@newsgroups.borland.com...

> Using a TThread it is not safe to use VCL components.

Not true.  You can use the thread's Synchronize() method to invoke a piece
of code in the context of the main VCL thread instead of the calling thread.
Then you can access VCL components from your thread code.

> But I'm wondering what exactly isn't safe. Are the VCL properties
> at risk, or is the underlying windows structure not safe?

The VCL is not thread-safe, for the most part.

> For instance, is it possible to lock the canvas of a VCL object
> in a thread and paint on it?

No.  Use Synchronize() to access the Canvas.

> Or is it possible to supply the windows handle to a thread to paint on it?

Possibly.

> Or should this all be done in the main thread.

Preferably, anything related to the GUI should be done in the main thread.


Gambit

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From: "Remy Lebeau \(TeamB\)" <gambit47@yahoo.com>
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Subject: Re: Thread synchronisation
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