Struct Packing and Memory Layout Questions

Covers how data structures are arranged in memory and how to control that layout for correctness and efficiency. Topics include alignment rules, padding between members, calculating sizes, use of packing pragmas and alignment attributes, and bit field behavior. Emphasis on designing structures for embedded systems and binary interfaces, ensuring portability across compilers and architectures, and techniques to verify layout such as static assertions and offset calculations. Also includes using structure based register overlays to represent device registers in code and correctly declaring members as volatile where appropriate to prevent unwanted compiler optimizations. Common pitfalls such as unintended padding, misaligned accesses, incorrect assumptions about endianness, and compiler specific extensions are covered.