HINSTANCE hinst; 
HWND hwndMain; 

int PASCAL WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, 
    LPSTR lpszCmdLine, int nCmdShow) 
{ 
    MSG msg; 
    BOOL bRet; 
    WNDCLASS wc; 
    UNREFERENCED_PARAMETER(lpszCmdLine); 

    // Register the window class for the main window. 

    if (!hPrevInstance) 
    { 
        wc.style = 0; 
        wc.lpfnWndProc = (WNDPROC) WndProc; 
        wc.cbClsExtra = 0; 
        wc.cbWndExtra = 0; 
        wc.hInstance = hInstance; 
        wc.hIcon = LoadIcon((HINSTANCE) NULL, 
            IDI_APPLICATION); 
        wc.hCursor = LoadCursor((HINSTANCE) NULL, 
            IDC_ARROW); 
        wc.hbrBackground = GetStockObject(WHITE_BRUSH); 
        wc.lpszMenuName =  "MainMenu"; 
        wc.lpszClassName = "MainWndClass"; 

        if (!RegisterClass(&wc)) 
            return FALSE; 
    } 

    hinst = hInstance;  // save instance handle 

    // Create the main window. 

    hwndMain = CreateWindow("MainWndClass", "Sample", 
        WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 
        CW_USEDEFAULT, CW_USEDEFAULT, (HWND) NULL, 
        (HMENU) NULL, hinst, (LPVOID) NULL); 

    // If the main window cannot be created, terminate 
    // the application. 

    if (!hwndMain) 
        return FALSE; 

    // Show the window and paint its contents. 

    ShowWindow(hwndMain, nCmdShow); 
    UpdateWindow(hwndMain); 

    // Start the message loop. 

    while( (bRet = GetMessage( &msg, NULL, 0, 0 )) != 0) 
    { 
        if (bRet == -1) 
        { 
            // handle the error and possibly exit 
        } 
        else 
        { 
            TranslateMessage(&msg); 
            DispatchMessage(&msg); 
        } 
    } 

    // Return the exit code to the system. 

    return msg.wParam; 
}

HWND hwndMain; 
HWND hwndDlgModeless = NULL; 
MSG msg;
BOOL bRet; 
HACCEL haccel; 
// 
// Perform initialization and create a main window. 
// 
 
while( (bRet = GetMessage( &msg, NULL, 0, 0 )) != 0)
{ 
    if (bRet == -1)
    {
        // handle the error and possibly exit
    }
    else
    {
        if (hwndDlgModeless == (HWND) NULL || 
                !IsDialogMessage(hwndDlgModeless, &msg) && 
                !TranslateAccelerator(hwndMain, haccel, 
                    &msg)) 
        { 
            TranslateMessage(&msg); 
            DispatchMessage(&msg); 
        }
    } 
} 

HWND hwnd; 
BOOL fDone; 
MSG msg; 
 
// Begin the operation and continue until it is complete 
// or until the user clicks the mouse or presses a key. 
 
fDone = FALSE; 
while (!fDone) 
{ 
    fDone = DoLengthyOperation(); // application-defined function 
 
    // Remove any messages that may be in the queue. If the 
    // queue contains any mouse or keyboard 
    // messages, end the operation. 
 
    while (PeekMessage(&msg, hwnd,  0, 0, PM_REMOVE)) 
    { 
        switch(msg.message) 
        { 
            case WM_LBUTTONDOWN: 
            case WM_RBUTTONDOWN: 
            case WM_KEYDOWN: 
                // 
                // Perform any required cleanup. 
                // 
                fDone = TRUE; 
        } 
    } 
} 

case WM_DESTROY: 
 
    // Perform cleanup tasks. 
 
    PostQuitMessage(0); 
    break; 

case WM_USER + 5: 
    if (InSendMessage()) 
        ReplyMessage(TRUE); 
 
    DialogBox(hInst, "MyDialogBox", hwndMain, (DLGPROC) MyDlgProc); 
    break; 

HWND hwndCombo; 
int cTxtLen; 
PSTR pszMem; 
 
switch (uMsg) 
{ 
    case WM_COMMAND: 
        switch (LOWORD(wParam)) 
        { 
            case IDD_ADDCBITEM: 
                // Get the handle of the combo box and the 
                // length of the string in the edit control 
                // of the combo box. 
 
                hwndCombo = GetDlgItem(hwndDlg, IDD_COMBO); 
                cTxtLen = GetWindowTextLength(hwndCombo); 
 
                // Allocate memory for the string and copy 
                // the string into the memory. 
 
                pszMem = (PSTR) VirtualAlloc((LPVOID) NULL, 
                    (DWORD) (cTxtLen + 1), MEM_COMMIT, 
                    PAGE_READWRITE); 
                GetWindowText(hwndCombo, pszMem, 
                    cTxtLen + 1); 
 
                // Add the string to the list box of the 
                // combo box and remove the string from the 
                // edit control of the combo box. 
 
                if (pszMem != NULL) 
                { 
                    SendDlgItemMessage(hwndDlg, IDD_COMBO, 
                        CB_ADDSTRING, 0, 
                        (DWORD) ((LPSTR) pszMem)); 
                    SetWindowText(hwndCombo, (LPSTR) NULL); 
                } 
 
                // Free the memory and return. 
 
                VirtualFree(pszMem, 0, MEM_RELEASE); 
                return TRUE; 
            // 
            // Process other dialog box commands. 
            // 
 
        } 
    // 
    // Process other dialog box messages. 
    // 
 
}