CWindow::GetWindowLong

Retrieves a 32-bit value at a specified offset into the extra window memory.

LONG GetWindowLong(
   int nIndex 
) const throw();

Заметки

See GetWindowLong in the Windows SDK.

Примечание.
To write code that is compatible with both 32-bit and 64-bit versions of Windows, use CWindow::GetWindowLongPtr.

Header: atlwin.h