參考資訊:
https://masm32.com/board/index.php
https://www.nasm.us/xdoc/2.13rc9/html/nasmdoc0.html
當視窗有事件需要被處理時,系統會透過呼叫註冊的Callback副程式來處理,而這個Callback副程式就是在註冊Class時,設定給lpfnWndProc的事件處理副程式,因此,當這個事件處理副程式被呼叫時,可以處理自己感興趣的事件,而其餘事件則交給系統處理(透過呼叫DefWindowProc()),需要注意的是,例如:WM_CLOSE,就必須由該視窗自己處理,因為系統無法知道還有哪些額外的資源需要被釋放掉
main.asm
%include "head.asm" segment .text WndProc: push ebp mov ebp, esp cmp dword [ebp + ARG2], WM_CLOSE je .handle_close cmp dword [ebp + ARG2], WM_DESTROY je .handle_destroy jmp .handle_default .handle_close: push dword [ebp + ARG1] call DestroyWindow xor eax, eax jmp .finish .handle_destroy: push 0 call PostQuitMessage xor eax, eax jmp .finish .handle_default: push dword [ebp + ARG4] push dword [ebp + ARG3] push dword [ebp + ARG2] push dword [ebp + ARG1] call DefWindowProc .finish: leave ret 16 WinMain: push ebp mov ebp, esp mov dword [wndClass + WNDCLASS.lpfnWndProc], WndProc mov dword [wndClass + WNDCLASS.lpszClassName], szAppName push wndClass call RegisterClass push 0 push 0 push 0 push 0 push 300 push 300 push 0 push 0 push WS_OVERLAPPEDWINDOW | WS_VISIBLE push szAppName push szAppName push WS_EX_LEFT call CreateWindowEx mov [hWin], eax .loop: push 0 push 0 push 0 push msg call GetMessage cmp eax, 0 je .exit push msg call DispatchMessage jmp .loop .exit: mov eax, [msg + MSG.wParam] leave ret 16 _start: push 0 call GetModuleHandle mov [hInstance], eax call GetCommandLine mov [pCommand], eax push SW_SHOWNORMAL push dword [pCommand] push 0 push dword [hInstance] call WinMain push eax call ExitProcess
Line 14~24:關閉視窗的順序為:主視窗收到WM_CLOSE事件時,呼叫DestroyWindow(),DestroyWindow()會自動將子視窗的相關資源也一併釋放掉(包含Resource描述的資源),系統接著會發送WM_DESTROY事件給主視窗,待主視窗收到WM_DESTROY事件時,呼叫PostQuitMessage()結束視窗,值得注意的地方是,SendMessage()是屬於Block方式呼叫(必須等待動作執行完畢才返回),而PostQuitMessage()則是Non-block方式呼叫
Line 26~31:其餘事件由系統代為處理
完成