Date: Thu, 09 Jan 2014 08:50:22 -0500 From: Ajtim <lumiwa@gmail.com> To: freebsd-questions@freebsd.org Cc: Frank Leonhardt <frank2@fjl.co.uk> Subject: Re: python warning Message-ID: <4495361.7qPzfLfjYJ@lumiwa.farms.net> In-Reply-To: <52CDA4B6.2020300@fjl.co.uk> References: <53434003.HmthDSXb49@lumiwa.farms.net> <52CDA4B6.2020300@fjl.co.uk>
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On Wednesday 08 January 2014 19:19:18 Frank Leonhardt wrote: > On 08/01/2014 18:37, Ajtim wrote: > > Hi! > > > > My system: > > FreeBSD 10.0-RC4 #0 r260130: Tue Dec 31 17:10:01 UTC 2013 root@snap.freebsd.org:/usr/obj/usr/src/sys/GENERIC amd64 > > > > I had bellow warnings in mail from version FreeBSD 10.0-ALPHA and it is still on. Do I need to make some settings or..., please? > > Thank you. > > > > +WARNING pid 1752 (python2.7): ioctl sign-extension ioctl ffffffff80087467 > > +WARNING pid 1762 (python2.7): ioctl sign-extension ioctl ffffffff80087467 > > I hate snakes! > > As to this, in case no one comes by that knows the answer, this wouldn't > worry me greatly. ioctl takes values that are unsigned long; generally > considered to be 32-bit unsigned values except when it's not. gcc > defaults to 64-bit on AMD64. I have a horrible feeling that CLANG > doesn't, and that FreeBSD 10 uses CLANG instead of gcc. I haven't been > brave enough to try it. OpenCL specifies that long will be 64-bit > regardless of platform, but that doesn't make it true. > > This is obviously bleating about a 64-bit value which looks like a -ve > 32-bit number (high bit set). Compilers moving a signed integer value > into a type with more bits WILL sign-extend, which means the high bit is > propagated through the "new" high-order bits. HOWEVER, when the device > driver is checking for commands it's not going to worry about the > high-order bits - if its expecting a 32-bit scalar but the architecture > gives it 64-bit instead it's not going to matter. It'll either check bit > 31 (which remains unchanged) or, worst case, test for -ve (in which case > you want the sign extend). It shouldn't do this, of course, because it's > not a signed number and therefore can only be +ve. Hence the bleat. > > Methinks there's probably a line in python that's calling ioctl with an > int instead of a ulong, and I bet CLANG comes in to it somewhere. > > Regards, Frank. > > > > > > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscribe@freebsd.org" Thank you very much for explanation. Looks like that is not bad but it is not nice everyday read "WARNINGS". -- Mitja ------- http://www.redbubble.com/people/lumiwa
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