🚀 go-pugleaf

I found a solution to my problem and I thought I'd post it here since
it was a bit obscure.

If you recall, I was creating several parentless non-child windows with:
 	CreateWindow("xxx",NULL,
 			WS_OVERLAPPED  | WS_CAPTION    |
 			WS_SYSMENU     | WS_THICKFRAME |
 			WS_MINIMIZEBOX | WS_MAXIMIZEBOX,
 			CW_USEDEFAULT,CW_USEDEFAULT,
 			CW_USEDEFAULT,CW_USEDEFAULT,
 			NULL,           //note - no parent
 			NULL,                           
			hinstance,(LPVOID)xxx);

I wanted them parentless so they wouldn't remain in front of the main
window.

When I closed the main window, these sub-windows disappeared, but when
I put a breakpoint at WM_DESTROY, it never got there (I guess Windows
destroyed them, but not through WM_DESTROY).  Anyway, they all used
resources that I wanted to free up before closing them.  I needed a
way to find all of these windows so I could send them WM_DESTROY.

Several people sent suggestions regarding EnumWindows and some said
I should keep a linked list of the HWND.  As simple as the linked
list code is, it just seemed to add yet more complexity to an already
complex app, so I looked for another solution.  Rick Kimmel came up
with the best ideas, so here is the (our) solution:

In the main window:
	  case WM_DESTROY:	DestroyOtherWindow(hwnd,"xxx");
				PostQuitMessage(0);
				break;

void DestroyOtherWindows(HWND hwndmain,char *classname)
{
HWND hwnd;
char buffer[50];

	hwnd=GetWindow(hwndmain,GW_HWNDFIRST);
	while(hwnd){
	  GetClassName(hwnd,buffer,sizeof(buffer));
	  if(strcmp(buffer,classname)==0){
	    if(GetWindowWord(hwnd,    GWW_HINSTANCE)==
	       GetWindowWord(hwndmain,GWW_HINSTANCE)){
	      		SendMessage(hwnd,WM_DESTROY,0,0);
	    }
	  }
	  hwnd=GetWindow(hwnd,GW_HWNDNEXT);
	}
	return;
}
-- 
John A. Grant						jagrant@emr1.emr.ca
Airborne Geophysics
Geological Survey of Canada, Ottawa