Checking if another window is closed c++ - c++

Question

I'm developing an application that checks open windows on a user computer on Windows (just like the Task Manager)
I used EnumWindows to list all the active window and it works, now i want to create a function that write a message on the console when a windows has been closed. Is possible or i have to check an array of WindowHandler in a separate thread and how do I check their status?
Thank for the help.

Answer 1

The easiest solution is to use WinEvents, by registering for EVENT_OBJECT_DESTROY events. The code is fairly straight forward:
#include <windows.h>
namespace {
HWINEVENTHOOK g_WindowDestructionHook = NULL;
}
inline void CALLBACK WinEventProc( HWINEVENTHOOK hWinEventHook,
DWORD event,
HWND hwnd,
LONG idObject,
LONG idChild,
DWORD dwEventThread,
DWORD dwmsEventTime ) {
// Filter interesting events only:
if ( idObject == OBJID_WINDOW && idChild == CHILDID_SELF ) {
wprintf( L"Window destroyed: HWND = %08X\n", hwnd );
}
}
inline void RegisterWindowDestructionHook() {
g_WindowDestructionHook = ::SetWinEventHook( EVENT_OBJECT_DESTROY,
EVENT_OBJECT_DESTROY,
NULL,
WinEventProc,
0, 0,
WINEVENT_OUTOFCONTEXT );
}
inline void UnregisterHook() {
::UnhookWinEvent( g_WindowDestructionHook );
}
Using this is equally simple:
::CoInitialize( NULL );
RegisterWindowDestructionHook();
MSG msg = {};
while ( ::GetMessageW( &msg, nullptr, 0, 0 ) > 0 ) {
::TranslateMessage( &msg );
::DispatchMessageW( &msg );
}
UnregisterHook();
::CoUninitialize();