directshow and cplus plus

If you want simulate the printscreen in C++.
Try this small example then...

#include <windows.h>
char EditText[256];
int EditTextLength;
/*  Declare Windows procedure  */
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);
 
/*  Make the class name into a global variable  */
char szClassName[ ] = "WindowsApp";
 
int WINAPI WinMain (HINSTANCE hThisInstance,
                    HINSTANCE hPrevInstance,
                    LPSTR lpszArgument,
                    int nCmdShow)
{
    HWND hwnd;               /* This is the handle for our window */
    MSG messages;            /* Here messages to the application are saved */
    WNDCLASSEX wincl;        /* Data structure for the windowclass */
 
    /* The Window structure */
    wincl.hInstance = hThisInstance;
    wincl.lpszClassName = szClassName;
    wincl.lpfnWndProc = WindowProcedure;      /* This function is called by windows */
    wincl.style = CS_DBLCLKS;                 /* Catch double-clicks */
    wincl.cbSize = sizeof (WNDCLASSEX);
 
    /* Use default icon and mouse-pointer */
    wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
    wincl.lpszMenuName = NULL;                 /* No menu */
    wincl.cbClsExtra = 0;                      /* No extra bytes after the window class */
    wincl.cbWndExtra = 0;                      /* structure or the window instance */
    /* Use Windows's default colour as the background of the window */
    wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;
 
    /* Register the window class, and if it fails quit the program */
    if (!RegisterClassEx (&wincl))
        return 0;
 
    /* The class is registered, let's create the program*/
    hwnd = CreateWindowEx (
               0,                   /* Extended possibilites for variation */
               szClassName,         /* Classname */
               "Clipboard Windows App",       /* Title Text */
               WS_OVERLAPPEDWINDOW, /* default window */
               CW_USEDEFAULT,       /* Windows decides the position */
               CW_USEDEFAULT,       /* where the window ends up on the screen */
               544,                 /* The programs width */
               375,                 /* and height in pixels */
               HWND_DESKTOP,        /* The window is a child-window to desktop */
               NULL,                /* No menu */
               hThisInstance,       /* Program Instance handler */
               NULL                 /* No Window Creation data */
           );
 
    /* Make the window visible on the screen */
    ShowWindow (hwnd, nCmdShow);
 
    /* Run the message loop. It will run until GetMessage() returns 0 */
    while (GetMessage (&messages, NULL, 0, 0))
    {
        /* Translate virtual-key messages into character messages */
        TranslateMessage(&messages);
        /* Send message to WindowProcedure */
        DispatchMessage(&messages);
    }
 
    /* The program return-value is 0 - The value that PostQuitMessage() gave */
    return messages.wParam;
}
 

/*  This function is called by the Windows function DispatchMessage()  */
 
LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    static HWND hwndButton;
    static HWND hwndEdit;
    HGLOBAL hGlobal;
    PSTR pGlobal;
 
    switch (message)                  /* handle the messages */
    {
    case WM_CREATE:
        hwndButton = CreateWindow ( TEXT ("button"),"Cut Text",WS_CHILD|WS_VISIBLE|1,55,100,100,25,hwnd,(HMENU) 1,((LPCREATESTRUCT) lParam) -> hInstance,NULL);
        hwndEdit = CreateWindow (TEXT ("edit"),NULL,WS_CHILD| ES_LEFT|WS_BORDER| WS_VISIBLE,55, 50, 100, 25, hwnd,
                                 (HMENU) 1,((LPCREATESTRUCT) lParam) -> hInstance ,NULL);
        return 0;
 
    case WM_COMMAND:
 
        switch (wParam)
        {
        case 1:
            EditTextLength = GetWindowTextLength(hwndEdit) +1;
            GetWindowText(hwndEdit, EditText, EditTextLength);
            hGlobal = GlobalAlloc(GHND|GMEM_SHARE,
                                  EditTextLength*sizeof (char));
            pGlobal = (char*)GlobalLock (hGlobal);
            strcpy (pGlobal, EditText);
            GlobalUnlock(hGlobal);
 
            OpenClipboard(hwnd);
            EmptyClipboard();
            SetClipboardData(CF_TEXT, hGlobal);
            CloseClipboard();
            break;
        }
        return 0;
 
    case WM_DESTROY:
        PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
        break;
    default:                      /* for messages that we don't deal with */
        return DefWindowProc (hwnd, message, wParam, lParam);
    }
 
    return 0;
}
 

</windows.h>