RFH: aliasing problems

[Ralf Corsepius]

On Fri, 2006-12-08 at 11:28 -0800, Till Straumann wrote:
> Welcome to the world, ralf :-)
> 
> This way of casting struct sockaddr * and struct sockaddr_xxx *
> (xxx for the address family) is done by every application using sockets
> (and they'll all get the type-punned pointer warning).


Neither Linux nor Solaris-2.7 exhibit this behavior with their sockaddr*
types and gcc-4.1.x. FreeBSD and RTEMS do.


Linux, Solaris and Cygwin have

struct sockaddr {
  sa_family_t sa_family;
  char sa_data[14];
};

struct sockaddr_xx {
  sa_family_t sa_family;
  ....
};


FreeBSD and RTEMS have:

struct sockaddr {
  unsigned char	sa_len;
  sa_family_t sa_family;
  char sa_data[14];
};

struct sockaddr_xx {
  unsigned char sa_len;
  sa_family_t sa_family;
  ...
};


So, how does this match with strict-aliasing rules?

Ralf