[Lazarus] tachart on mousemove

[Andrea Mauri]

On 04/23/2010 11:58 AM, John vd Waeter wrote:
> AFAIK: In Windows
>
> PostMessage puts a message in the queue and returns immediately.
>
> SendMessage puts the message in the queue and returns with a result
> after the message has been handled.
>
> But I might be wrong...

You might be right.

Yet, I only played with SendMessage to do communication between two or
more Delphi applications in Windows. Here the receiving functionality is
"procedure ... message" and I did not find a documentation that states
that the sending process (better: thread) is supposed to be blocked in
SendMessage until the receiving process finished it's message procedure.
It should be easy to try this by doing a sleep in the message procedure,
but the result might be invalid, as the receiver's RTL could first
acknowledge the message to the System (whatever that means) and only
call the pascal code afterwards.

-Michael