From: Clifford Heath <cjh_nospam@...>
Date: 2003-09-12T09:55:36+09:00
Subject: Re: Nested struct alignment summarized

I solved the same problem for my C++ DDT (Dynamic Data Typing)
library. The difficulty is that the same compiler may have many
different sets of structure alignment rules. For example, with
the Microsoft compilers, you can use "#pragma pack(N)" to tell
the compiler to apply different minimum alignment for any struct.
The Windows APIs *actually use* this pragma, so any code to mimic
the memory layout must have not only a list of the field types,
but also of the rules being used. A nested structure might even
have different alignment rules than the structure inside which
it's nested, and all this is platform dependent. Unless you're
prepared to wear limiting yourself to a single chosen set of
alignment rules, or to provide possibly many platform-specific
hints in your metadata (I did both, chosen default with optional
annotations), you're SOL.

Clifford.