struct-ret-2.c

this is a gcc file, you can download it and learn its usetility, for further detail please look at t

typedef struct
{
  unsigned char a __attribute__ ((packed));
  unsigned short b __attribute__ ((packed));
} three_byte_t;

unsigned char
f (void)
{
  return 0xab;
}

unsigned short
g (void)
{
  return 0x1234;
}

main ()
{
  three_byte_t three_byte;

  three_byte.a = f ();
  three_byte.b = g ();
  if (three_byte.a != 0xab || three_byte.b != 0x1234)
    abort ();
  exit (0);
}