SetWindowLong / GetWindowLong and 32-bit / 64-bit processors

Question

I am using the following code:

const int GWL_STYLE = (-16); const UInt32 WS_POPUP = 0x80000000; const UInt32 WS_CHILD = 0x40000000; [DllImport("user32.dll", SetLastError = true)] static extern UInt32 GetWindowLong(IntPtr hWnd, int nIndex); [DllImport("user32.dll")] static extern int SetWindowLong(IntPtr hWnd, int nIndex, UInt32 dwNewLong); 

and somewhere ...

 SetWindowLong(this.Handle, GWL_STYLE, ((GetWindowLong(this.Handle, GWL_STYLE) & ~(WS_POPUP)) | WS_CHILD)); 

Will this work on both 32-bit and 64-bit machines?

If not, if I compile my application to run as an x86 process, will it still work on a 64-bit machine?

And how can I rewrite the following code in order on both 32-bit and 64-bit machines?

Answer 1

I think you're wondering if you chose the UInt32 type correctly. The answer is yes. The docs clearly say that this is always a 32-bit value: http://msdn.microsoft.com/en-us/library/windows/desktop/ms633591(v=vs.85).aspx

The correct code.