🚀 go-pugleaf

"Rodrigo" <rmorteo@eudoramail.com> wrote in message
news:401157db$2@newsgroups.borland.com...

> 1.- When watching the values of SHELLEXECUTEINFO,
> the instance retrieved by GetWindowLong appears to be more
> similar to the hProcess value than the hInstApp value (see the
> GetWinHandle function below).

Like its brother ShellExecute(), the returned HINSTANCE is not always a true
handle.  You would be better off working with process handles instead.
Since ShellExecuteEx() does not return a process ID, only a process handle,
your callback function will need to use GetWindowThreadProcessId() to get a
process ID and then use OpenProcess() to get a process handle that you can
compare with.  Otherwise, change to use CreateProcess() instead so that you
can compare IDs instead of handles.

> 2.- I couldn't make the callback function belong to the TMainForm
> class because compiler showed a message telling that the function
> must be called or its address taken...

That is correct.  The callback needs to be a standalone function.  It cannot
be a member of a class at all, unless it is declared as 'static'.  The
signature of a class method vs. a standalone function is very different.

> 4.-For what I understood from the documentation of both API functions,
> EnumWindows should loop until callback returns false

You should be using TRUE and FALSE, not 'true' and 'false'.  BOOL is not a
'bool'.

> HWND TMainForm::LookForWindowHandle(HANDLE Hinstance)
> {
>      unsigned long temp;
>      temp=(long)Hinstance;
>      if (!EnumWindows((WNDENUMPROC)GetWinHandle,temp))
>           return swProcess; //global variable
>      else
>           return 0;
> }

You don't need to use a separate variable, you could pass the HInstance to
EnumWindows() directly:

    HWND TMainForm::LookForWindowHandle(HANDLE Hinstance)
    {
        if( !EnumWindows((WNDENUMPROC)GetWinHandle, (LPARAM)Hinstance) )
            return swProcess; //global variable
        else
            return 0;
    }

I would also suggest that you not name your variable as "HInstance".  The
VCL already has a global variable by that same name.

Also, I would suggest avvoiding the use of a global variable to return the
found window handle.  You can use a structure instead in order to keep
everything local:

    struct TWindowInfo
    {
        HINSTANCE hInst;
        HWND hWnd;
    };

    HWND TMainForm::LookForWindowHandle(HANDLE Hinst)
    {
        TWindowInfo info;
        info.hInst = Hinst;
        info.hWnd = NULL;
        EnumWindows((WNDENUMPROC)GetWinHandle, (LPARAM)&info);
        return info.hWnd;
    }

    BOOL CALLBACK GetWinHandle(HWND hwnd, LPARAM lParam)
    {
        TWindowInfo *pInfo = (TWindowInfo*)lParam;
        if( GetWindowLong(hwnd, GWL_HINSTANCE) == pInfo->hInst )
        {
            pInfo->hWnd = hwnd;
            return FALSE;
        }
        else
            return TRUE;
    }


Gambit