Borland® Delphi™ 6 Developer's Guide

Migrating from Delphi 3

Although there aren't a great deal of compatibility issues between Delphi 3 and later versions, the few issues that do exist can be potentially more problematic than porting from any other previous version of Delphi to the next. Most of these issues revolve around new types and the changing behavior of certain existing types.

Unsigned 32-bit Integers

Delphi 4 introduced the LongWord type, which is an unsigned 32-bit integer. In previous versions of Delphi, the largest integer type was a signed 32-bit integer. Because of this, many of the types that you would expect to be unsigned, such as DWORD, UINT, HResult, HWND, HINSTANCE, and other handle types, were defined simply as Integers. In Delphi 4 and later, these types are ...