> As for RV64 and Arm64 This was just a placeholder, perhaps a bad example. I program a proprietary CPU architecture which does not require alignment. And for

> As for RV64 and Arm64 This was just a placeholder, perhaps a bad example. I program a proprietary CPU architecture which does not require alignment. And for which the compiler naturally prefers to pack structs. Getting it to mimick Arm style struct padding is much harder and error prone than just having the Arm pack everything. Maybe you are right and we are heading for a One True Struct Layout in the future. Today I think it is still too scary to pass the same unpacked struct declaration to various compiler archs and hope they come up with the same interpretation.