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Date: Tue, 17 Jul 2012 11:27:26 +0200 From: Eugen Dedu <Eugen.Dedu@...pm.univ-fcomte.fr> To: linux-kernel@...r.kernel.org Subject: getsockopt/setsockopt with SO_RCVBUF and SO_SNDBUF "non-standard" behaviour Hi all, I looked on Internet and at the old thread http://lkml.indiana.edu/hypermail/linux/kernel/0108.0/0275.html, but the issue is still not settled as far as I see. I need to have the highest memory available for snd/rcv buffer and I need to know/confirm how much it allocated for my process (how much I can use). So with Linux we need to do something like: setsockopt (..., SO_RCVBUF, 256000, ...) getsockopt (..., SO_RCVBUF, &i, ...) i /= 2; where i is the size I am looking for. Now, to make this code work for other OSes it should be changed to: setsockopt (..., SO_RCVBUF, 256000, ...) getsockopt (..., SO_RCVBUF, &i, ...) #ifdef LINUX i /= 2; #endif First question, is this code correct? If not, what code gives the amount of memory useable for my process? Second, it seems to me that linux is definitely "non-standard" here. Saying that linux uses twice as memory has nothing to do with that, since getsockopt should return what the application can count on, not what is the internal use. It is like a hypothetical malloc (10) would return not 10, but 20 (including meta-information). Is that right? Cheers, -- Eugen Dedu http://eugen.dedu.free.fr -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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