🚀 go-pugleaf

Mike Collins wrote:

>Basically a ProcessA calls my DLL and makes available some functions for my 
>DLL by passing my DLL a pointer to a specific structure.  My DLL has two 
>threads, it's main thread (threadM) and a secondary one that examines some 
>hardware (threadH).  If a certain hardware condition occurs, I need to call 
>one of the functions in the calling processA.  However, if threadH calls the 
>exported function, the whole system can, on occasion stop working correctly 
>or work sporadically.

So, really, your dll creates One thread (threadH), and your theadM is
actually ProcessA?
So, you want ProcessA to call the function.
You could tell the author of ProcessA to handle your special message.
Or you could create a global hook that gets injected into ProcessA's
message handling.

See  SetWindowsHookEx()

You might Google for code that Remy has posted several times.

>1) Are there any specific properties, other than HWND_MESSAGE as the 
>hWndParent, that I need to set in either WNDCLASS / WNDCLASSEX or 
>RegisterClass / RegisterClassEx in my specific situation?

I don't think so.

>2) Do I need to call ShowWindow() or UpdateWindow in this particular context 
>as I don't really have a window to show?

I don't think so, or maybe with SW_SHOW_HIDDEN

>3) Do I specifically have code the while(GetMessage()) loop or can I rely on 
	Yes
>the WndProc to detect and capture my custom messages?  I only ask this 
	No
>because it would seem to me that if I have a while loop in the start-up of 
>my DLL's main thread, it would then in effect pause the thread as it would 
>be sitting in that loop.
	Yes. That's why you used CreateProcess or CreateThread
>4) I want to ensure that no other processes can attempt to close or 
>terminate this hidden window - what is the best way to prevent this.
	Best way to prevent that is to not do it this way.