Manual states clong is always Int64
The manual page states type clong = Int64;, which is incorrect:
{$ifdef cpu64}
clong = int64; pclong = ^clong;
cslong = int64; pcslong = ^cslong;
culong = qword; pculong = ^culong;
{$else}
clong = longint; pclong = ^clong;
cslong = longint; pcslong = ^cslong;
culong = cardinal; pculong = ^culong;
{$endif}