Messages in this thread | | | Date | Mon, 12 Apr 1999 10:53:19 +0200 | From | Vojtech Pavlik <> | Subject | Re: [OFFTOPIC?] Re: 2.2.x kernels missend odd-sized ICMP pa |
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On Sun, Apr 11, 1999 at 09:51:35PM -0400, Horst von Brand wrote:
> (This is an excerpt from ping.c:in_cksum in netkit-0.10, sent to me by Petr > Vandrovec): > > register u_short *w = addr; > register int sum = 0; > u_short answer = 0; > .... > *(u_char*)(&answer) = *(u_char*)w; > sum += answer; > > This is a dumb way to write this. > > egcs-19990405 generates code that gets the right value, others (including > egcs-1.0.3 used to build RedHat-5.2, AFAIKS) break, as they don't respect > the initialization and put a random byte in the higher half. > > A better way to write the above is just: > > sum += *(u_char*)w;
But, isn't this a compiler bug anyway? It shouldn't ignore the initialization in this case - actually I wonder why it would decide to.
Vojtech
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