Re: [PATCH 5/5] struct sockaddr_storage->ss_family is not portable

> On Thu, Mar 11, 2010 at 06:40:37PM +0200, Martin Storsj? wrote:
> > On Thu, 11 Mar 2010, Gary V. Vaughan wrote:
> > 
> > > Many of our supported platforms do not have this declaration, for
> > > example solaris2.6 thru 2.7.  Lack of ss_family implies no IPV6
> > > support, so we can wrap all the ss_family references in an ifndef
> > > NO_IPV6, and assume sockaddr_in otherwise.
> > 
> > While this probably is ok as such, you can actually do the same without 
> > accessing the sockaddr_storage->ss_family; just cast it to (const struct 
> > sockaddr*) and use ->sa_family instead, that should work just as well, as 
> > far as I know.
> 
> At least on aix-5.2 it won't be reliable unless you juggle compiler
> switches just right (I didn't check anywhere else, but the precedent
> for the bit ordering of the struct members being different is already
> set):
> 
> #if defined(COMPAT_43) && !defined(_KERNEL)
> struct sockaddr {
>         ushort_t        sa_family;      /* address family */
>         char            sa_data[14];    /* up to 14 bytes of direct
> address */
> };
> 
> 
> #else
> struct sockaddr {
>         uchar_t         sa_len;         /* total length */
>         sa_family_t     sa_family;      /* address family */
>         char            sa_data[14];    /* actually longer; address value */
> };
> #endif