How this works
Assumes the common natural-alignment rule most compilers (GCC/Clang, default settings) use: each member is aligned to its own size (capped at the platform word/pointer size, treated here as 8 bytes), and the struct's total size is padded up to a multiple of its largest member's alignment. This is an estimate, not a guarantee — #pragma pack, __attribute__((packed)), bitfields, and unusual compilers/ABIs can all change the real layout, so always verify with sizeof() or offsetof() on your actual target.