Этот пример показывает как можно отслеживать - с какими окнами в системе работает   пользователь. То есть при нажатии на Титле бар , минимизации, закрытии окна

СКАЧАТЬ (~4Kb)

#define STRICT
#include 
#include "resource.h"

const char *pszTitle = "Descriptor Systems Mouse Capture Example";

// internal function prototypes
LRESULT CALLBACK WndProc ( HWND hwnd, UINT iMsg
                         , WPARAM wParam, LPARAM lParam );

int PASCAL WinMain ( HINSTANCE hInstance, HINSTANCE hPrevInstance
                   , LPSTR  lpszCmdLine, int    nCmdShow )
{
HWND        hwnd;                       // window handle
WNDCLASS    wndclass;                   // class structure
MSG         msg;                        // msg data structure


  // register only if this is the first instance
    if (!hPrevInstance)
    {
        wndclass.style         = CS_HREDRAW | CS_VREDRAW;
        wndclass.lpfnWndProc   = WndProc;
        wndclass.cbClsExtra    = 0;
        wndclass.cbWndExtra    = 0;
        wndclass.hInstance     = hInstance;
        wndclass.hIcon         = LoadIcon ( hInstance
                                    , MAKEINTRESOURCE ( IDI_MYICON ));
        wndclass.hCursor       = LoadCursor ( 0, IDC_ARROW );
        wndclass.hbrBackground = (HBRUSH)GetStockObject ( WHITE_BRUSH );
        wndclass.lpszMenuName  = MAKEINTRESOURCE ( IDM_MENU );
        wndclass.lpszClassName = "Template";

  // attempt to register -- exit if we can't
        if ( !RegisterClass ( &wndclass ) )
            return 0;
    }

  // create a window based on the class we just registered
    hwnd = CreateWindow (
                "Template"          // class name
              , pszTitle            // window caption (title)
              , WS_OVERLAPPEDWINDOW // style
              , CW_USEDEFAULT       // initial x
              , CW_USEDEFAULT       // initial y
              , CW_USEDEFAULT       // initial cx
              , CW_USEDEFAULT       // initial cy
              , 0                   // no parent
              , 0                   // no menu
              , hInstance           // instance handle
              , NULL );             // no create parameters

    if ( hwnd == 0 )
        return 0;

  // show the window and force it to paint
    ShowWindow   ( hwnd, nCmdShow );
    UpdateWindow ( hwnd );

  // enter the event loop -- remain in loop until window closes
    while ( GetMessage ( &msg, NULL, 0, 0 ) != FALSE )
    {
        DispatchMessage  ( &msg );
    }

    return msg.wParam;
}

//**********************************************************
LRESULT CALLBACK WndProc ( HWND hwnd, UINT iMsg
                         , WPARAM wParam, LPARAM lParam )
{

    switch ( iMsg )
    {
        case WM_DESTROY:
            PostQuitMessage (0);
            return 0;

        case WM_COMMAND:
            {
                switch ( LOWORD ( wParam ) )
                {
                    case IDM_CHOOSE:
                        {
                            MessageBox ( hwnd, "Click on any window"
                                       , "Choose a window"
                                       , MB_OK | MB_ICONINFORMATION );

                            SetCapture ( hwnd );
                        }
                        break;
                }
            }
            return 0;

        case WM_LBUTTONUP:
            {
                if ( GetCapture () == hwnd )
                {
                    POINT   pt;

                  // retrieve the mouse coordinates
                    pt.x = (short)LOWORD ( lParam );
                    pt.y = (short)HIWORD ( lParam );

                  // convert to screen units
                    ClientToScreen ( hwnd, &pt );

                  // determine handle of window under the click
                    HWND    hwndClick = WindowFromPoint ( pt );

                  // display the window's text
                    if ( hwndClick != 0 )
                    {
                        char   szText[255];

                        GetWindowText ( hwndClick, szText
                                      , sizeof szText );

                        MessageBox ( hwnd, szText, "You clicked on"
                                   , MB_OK | MB_ICONINFORMATION );
                    }

                  // release the mouse capture
                    ReleaseCapture ();
                }
            }

        case WM_PAINT:
            {
                PAINTSTRUCT     ps;

                BeginPaint ( hwnd, &ps );

                RECT    rc;

                GetClientRect ( hwnd, &rc );

                DrawText ( ps.hdc
                         , "Select \"Choose Window\" from the menu"
                         , -1, &rc
                         , DT_SINGLELINE | DT_CENTER | DT_VCENTER );

                EndPaint ( hwnd, &ps );
            }
            return 0;

        default:
            return DefWindowProc ( hwnd, iMsg, wParam, lParam);
    }
}