Re: struct sockaddr_storage

[Andreas Schwab <schwab@issan.cs.uni-dortmund.de>]

Philip Blundell <philb@gnu.org> writes:

|> Here's a patch to add a definition for `struct sockaddr_storage', which was 
|> introduced by the IPv6 API.  The intention is that it provides a block of 
|> memory with sufficient size and alignment that you can cast it to any `struct 
|> sockaddr_xxx *' and get sensible behaviour.
|> 
|> Please check that it doesn't cause any breakage, especially on Hurd and MIPS.
|> 
|> p.
|> 
|> 1999-05-10  Philip Blundell  <philb@gnu.org>
|> 
|> 	* sysdeps/generic/bits/socket.h (struct sockaddr_storage): New
|>  	structure; storage suitable for any socket address.
|> 	* sysdeps/unix/sysv/linux/bits/socket.h: Likewise.
|> 	* sysdeps/unix/sysv/linux/mips/bits/socket.h: Likewise.
|> 
|> --- libc/sysdeps/generic/bits/socket.h	Fri Apr 24 21:52:30 1998
|> +++ libc/sysdeps/generic/bits/socket.h	Mon May 10 20:03:52 1999
|> @@ -127,6 +127,25 @@
|>    };
|>  
|>  
|> +/* Structure large enough to hold any socket address (with the historical
|> +   exception of AF_UNIX).  We reserve 128 bytes.  */
|> +#include <sys/types.h>
|> +#if (~0UL) > 0xffffffff

This is wrong.  The preprocessor must use the widest type for evaluation,
which is intmax_t in C9x, so that ~0U is _always_ bigger than 0xffffffff
(independent of the suffix, which is ignored by the preprocessor, and
intmax_t must have at least 64 bits).  You must use ULONG_MAX instead.

Andreas.

-- 
Andreas Schwab                                      "And now for something
schwab@issan.cs.uni-dortmund.de                      completely different"
schwab@gnu.org