Another Windows challenge:

I'm trying to get the title of the active window even if it is from an external application. This is what I've come up with so far:

<D>
import std.stdio;
import core.sys.windows.windows;

extern (Windows)

void main()
{
	HWND foreground = GetForegroundWindow();
	const(wchar) title;

	int length = SendMessage(foreground, WM_GETTEXTLENGTH, 0, 0);
	SendMessage(foreground, WM_GETTEXT, length, LPARAM(title));			//LPARAM is a Long Pointer

	writeln(length);
	writeln(title);

}
</D>

Outputs :

27                                                                                                                      ´┐┐

So the lengt of the foreground windows title should be 27 chars long, but the title is only 3 chars (and kinda funny ones too:-(

Anyone ideas?

On Sunday, 4 November 2018 at 19:06:22 UTC, Mark Moorhen wrote:
> Another Windows challenge:
>
> I'm trying to get the title of the active window even if it is from an external application. This is what I've come up with so far:
>
> <D>
> import std.stdio;
> import core.sys.windows.windows;
>
> extern (Windows)
>
> void main()
> {
> 	HWND foreground = GetForegroundWindow();
> 	const(wchar) title;
>
> 	int length = SendMessage(foreground, WM_GETTEXTLENGTH, 0, 0);
> 	SendMessage(foreground, WM_GETTEXT, length, LPARAM(title));			//LPARAM is a Long Pointer
>
> 	writeln(length);
> 	writeln(title);
>
> }
> </D>
>
> Outputs :
>
> 27
>                                                       ´┐┐
>
> So the lengt of the foreground windows title should be 27 chars long, but the title is only 3 chars (and kinda funny ones too:-(
>
> Anyone ideas?

You need to allocate some memory to receive the string from WM_GETTEXT.

  auto length = SendMessage(foreground, WM_GETTEXTLENGTH, 0, 0);
  auto buffer = new wchar[length + 1]; // +1 for the trailing null character
  SendMessage(foreground, WM_GETTEXT, buffer.length, cast(LPARAM)buffer.ptr);
  auto title = cast(wstring)buffer[0 .. length];
  writeln(title);

Brilliant! Thanks John
!