WTF GCC, why pad my structs?

  struct fields {
    uint8_t f1;
    uint16_t f2;
    uint8_t f3;
  }

Of course not! Ever heard of this "memory alignment" thing? There even were architectures where accessing an unaligned int would get you SIGBUS (Solaris/SPARC was one, from what I remember). Have you never wondered where all the unix signals came from?