On Wed, Jul 16, 2014 at 10:55:57AM +0200, Florian Weimer wrote: > On 07/15/2014 07:22 PM, Adam Jackson wrote: > >On Tue, 2014-07-15 at 10:40 -0600, Orion Poplawski wrote: > >>Did you know that "char" defaults to "signed char" on x86 but "unsigned char" > >>on ppc and arm? I didn't. > > > >Yep, found that out the hard way. It annoyed me enough that I went > >digging in the gcc source to find the answer for all platforms: > > > >http://ajax.fedorapeople.org/is-char-signed-or-not.txt > > Any idea why aarch64 and ppc64le got this wrong? Why is char == unsigned char wrong? Because i?86/x86_64 do it differently? The decision for whether char is signed or unsigned historically is about what is more efficient in the ISA, of course once it goes into the ABI, it is part of the ABI. The reason aarch64 chose to use unsigned is most likely because it has ARM roots, which has unsigned char too. And similarly for ppc64le. Jakub -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel Fedora Code of Conduct: http://fedoraproject.org/code-of-conduct
