🚀 go-pugleaf

Hmm.... that makes sense about the checkboxes. On further review, I realize that
my code does exactly what you say. I have internal bool variables that are
altered by the GUI checkboxes. I must have run into something similar a few
years back. ;)

Display() uses...

HDC hDC = GetDC(hWindow);

hWindow is passed in as ShellForm->Handle which I assume is the handle to the
window? (ShellForm is my main window, built from TCustomForm by BDS)

So if both threads are accessing the same memory then they'll still be waiting
on each other, and I wouldn't have seen it until now with this new
dual-processor? And TThread won't help me one bit, eh? ;)

Thanks,

Rob



Jonathan Benedicto wrote:
> 
>> 'process()' does nothing unless check marks are set in additional GUI
>> window. No
>> functions are called from this routine as no checkmarks are checked.
>> ex. if (VideoForm->BlurImage->Checked) BlurVideoImage();
> 
> That does not sound like that function is thread-safe. I'd use a couple
> bools to store the state of the checkboxes, and then check the bools in
> the thread, instead of checking the actual checkboxes.
> 
> 
>> 'display()' calls SendDIBitsToDevice()
> 
> Where do you get the device handle to pass to SendDIBitsToDevice?
> 
> 
>> Really, these threads should run independent of each other (I hope).
> 
> Yes they do, however, they access data that is used by both threads, and
> if the access is not written in a thread-safe manner, it will not work
> properly.
> 
> Jon