RE: [lwip-devel] [PATCH] Fix aliasing violation.

[bill]

But we should use SMEMCPY.  I use a macro that converts this to a series of 
inline load/stores.

Bill

> -----Original Message-----
> From: address@hidden
> [mailto:address@hidden On
> Behalf Of David Woodhouse
> Sent: Friday, October 03, 2008 5:43 AM
> To: lwip-devel
> Subject: [lwip-devel] [PATCH] Fix aliasing violation.
> 
> src/netif/etharp.c: In function ‘etharp_arp_input’:
> src/netif/etharp.c:708: warning: dereferencing type-punned pointer will
> break strict-aliasing rules
> 
> Index: src/netif/etharp.c
> ===================================================================
> RCS file: /sources/lwip/lwip/src/netif/etharp.c,v
> retrieving revision 1.148
> diff -u -p -r1.148 etharp.c
> --- src/netif/etharp.c        19 Jun 2008 16:40:59 -0000      1.148
> +++ src/netif/etharp.c        3 Oct 2008 09:39:55 -0000
> @@ -705,7 +705,7 @@ etharp_arp_input(struct netif *netif, st
>        hdr->opcode = htons(ARP_REPLY);
> 
>        hdr->dipaddr = hdr->sipaddr;
> -      hdr->sipaddr = *(struct ip_addr2 *)&netif->ip_addr;
> +      memcpy(&hdr->sipaddr, &netif->ip_addr, sizeof(hdr->sipaddr));
> 
>        LWIP_ASSERT("netif->hwaddr_len must be the same as
> ETHARP_HWADDR_LEN for etharp!",
>                    (netif->hwaddr_len == ETHARP_HWADDR_LEN));
> 
> --
> David Woodhouse                            Open Source Technology
> Centre
> address@hidden                              Intel
> Corporation
> 
> 
> 
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