Does GCC's __attribute__((__packed__)) retain the original ordering?

Question

Purpose

I am writing a network program in C (specifically gnu89) and I would like to simplify things by reinterpreting a certain

Answer 1

We use this technique frequently to convert messages between a byte array and a structure, and have never encountered problems with it. You may have to perform endianness conversion yourself, but field order isn't a problem. If you have any concerns about data type sizes, you can always specify field size like so:

struct foo
{
  short someField : 16 __attribute__ ((packed));
};

This guarantees that someField will be stored as 16 bits and will not be rearranged or altered to fit byte boundaries.