What does “Packed Now Forces Byte Alignment of Records” mean?

Question

The What\'s New for Delphi XE2 contains the following.

Packed Now Forces Byte Alignment of Records

If you have legacy code that uses the

Answer 1

As far as I remember, record used to be packed since a version of the compiler around Delphi 5-6.

Then, for performance reasons, plain record fields were aligned, according to the settings in the project option. If you define a packed record there won't be any alignment within the record.

The text you are quoting seems related not specifically to XE2, but to a Delphi 2009 change. See this Blog entry for historical purpose.

I guess that "'Packed' Now Forces Byte Alignment of Records" refers to the Delphi 2009 {$OLDTYPELAYOUT ON} feature - which may have some implementation issue before XE2. I agree with you: it sounds like a documentation issue.