[ddtaylor]

C allows most of this, whereas C++ doesn't allow pointer aliasing without a compiler flag, tricks and problems.

I agree you can certainly just use bytes of the correct sizes, but often to get the coverage you need for the data structure you end up writing some form of wrapper or fixup code, which is still easier and gives you the control versus most of the protobuf like stuff that introduces a lot of complexity and tons of code.

[nly]

__attribute__((may_alias, packed)) right on the struct.

[amluto]

Check your generated code. Most compilers assume that packed also means unaligned and will generate unaligned load and store sequences, which are large, slow, and may lose whatever atomicity properties they might have had.

[johannes1234321]

That is not C, but a non-standard extension and thus not portable.

[josefx]

> non-standard extension and thus not portable

Modern versions of standard C aren't very portable either, unless you plan to stick to the original version of K&R C you have to pick and choose which implementations you plan to support.

[ddtaylor]

I disagree. Modern C with C17 and C23 make this less of an issue. Sure, some vendors suck and some people take shortcuts with embedded systems, but the standard is there and adopted by GCC, Clang and even MSVC has shaped up a bit.

[josefx]

> GCC, Clang and even MSVC

Well, if that is the standard for portability then may_alias might as well be standard. GCC and Clang support it and MSVC doesn't implement the affected optimization as far as I can find.

[ddtaylor]

What do you think the standard is for standardization?