Question

I don’t really understand this ‘incompatible types’ error (Delphi XE2)

function TWaveBase.GetHandle: THandle;
begin
  if HandleNeeded then begin
    if HandleAllocated then
      CloseHandle;
    CreateHandle(False);
  end;
  FHandleNeeded:=False;
  Result:=FHandle;
end;

[…]

property Handle:Cardinal read GetHandle; -> error here

Answer 1

THandle is a type declared based on Cardinal in Delphi XE. (Because of 64-bit and cross-platform, it’s defined as NativeUInt in XE2). It’s a new type.

If your GetHandle getter is returning a THandle, your property should also be declared as a THandle. Change it and things should work fine.