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A comment on The Byte Order Fiasco. Parent comment

Re:The Byte Order Fiasco by cbmuser on Saturday May 08, 2021 @09:00AM (#27086767)
You are still casting one pointer type into another which can result in unaligned access.

If you need to change byte orders, you should use library to achieve that.

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Re:The Byte Order Fiasco by nly on Saturday May 08, 2021 @09:10AM (#27086818)
Boost.Endian is the library here and this code is safe because the big_uint32_t type has an alignment requirement of 1 byte.

This is why ubsan is silent and not even injecting a check in to the compiled code.

You can check the alignment constraints with static_assert (something else you can't do in standard C): https://gcc.godbolt.org/z/KTcf9ax6r

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Re:The Byte Order Fiasco by kevin_thibedeau on Saturday May 08, 2021 @11:27AM (#27087988)
C11 has static_assert: https://gcc.godbolt.org/z/E3bGc95o3

Is also has _Generic() so you can roll up a family of endianness conversion functions and safely change types without blowing up somewhere else with a hardcoded conversion routine.

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