Classic use case: creating a packed structures to directly read TCP packets. There is still the "convert from big to little endian" problem, but I think you can

Classic use case: creating a packed structures to directly read TCP packets. There is still the "convert from big to little endian" problem, but I think you can use GCC's method for individually packing a struct: struct TCP_Packet { uint16_t source_port; uint16_t dest_port; uint32_t seq_no; uint16_t flags; uint16_t window_size; uint16_t checksum; unit16_t urgent; ... } __attribute__ ((packed));