alt Hacker Newsstruct layout is well specified, it should be possible to avoid any padding issues by just aligning and by padding (with dummy members) correctly. The problem in practice is mostly integer representation (big-endian vs little-endian).
Replies
> struct layout is well specified
Technically that's not true at least for booleans and enums, the C standard doesn't define specific sizes for those (bools are commonly 1 byte though, but for enums at least MSVC likes to disagree with Clang and GCC).
Using a direct struct memory layout for persistency and then expecting it to work across compilers, CPUs and ABIs is almost guaranteed to cause problems.
If you modify or even just move fields around the struct that also changes the way they are serialized...
You really need a serializer for this sort of thing because it can also include forwards compatibility of your data structures.
Specified by whom? Not the C standard for sure. It is indeed soecified by individual ABIs, and ABIs don't tend to do anything too weird, but that's another question.