-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi Moritz,
thanks :) I agree on the "let's not break builds for the pure beauty of #pragma once" approach. I tried this only to find existing bugs, and actually found very little; however, they could be completely avoided by #pragma once, and therefore I do see value in using it. So I humbly and slightly disagree with the "my editor does that for me" approach. Since I couldn't find info on which compilers are minimally necessary to build GR, I tried to figure out on my own(0). So far, I've not quite come to any useful point. Boost uses the classical include guards, but adds a #pragma once only for MSVC compilers(1) so those might really profit from that. Reading the gcc 3.4 release notes (2) suggests that prior to 3.4, #pragma once was but deprecated -- showing a few warnings in an ancient compiler doesn't seem to be too bad ;) So I read on (3) and found out that in fact, #pragma once had problems in gcc < 3.4 (3.2 being the oldest gcc I've actually witnessed in the wild, these are not many) due to it not dealing with hard- and symlinks properly. However, with our current source tree and build methodology, this will not be critical. The only versions that would actually produce warnings were some early gcc 3.3, after the problem was found and before the pragma was un-deprecated again, so I think you will hardly find someone using a compiler where this would do as much as warn you that there is an deprecated pragma in use in the GNU toolchain world. So. The question stays the same: just *how* weird can build platforms for GR be? I don't have a raging clue what people use on their embedded devices where they'd actually try to compile GR 3.7 for, so I can't really make a stand here. Greetings, Marcus (0) If anyone knows how to get a non-interfering but working gcc3.2 on a current fedora, let me know. (1) o.O (2) http://gcc.gnu.org/gcc-3.4/changes.html, search for #pragma once (3) http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11569 (4) http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11569#c12 On 23.02.2014 20:03, Moritz Fischer wrote: > Hi Marcus, > > some quick Google research found several contradictory sources. > [1] calls it 'non standard but widely supported'. Since we build on > weird platforms I think we should make absolutely sure that this is > the way things should be done ^{TM}. Some other sources listed this > as a potential speedup for compilation on Visual Studio. Discuss. > > Personally I don't have an issue with header guards because there > exist plenty of plugins for {vim,emacs, whatever}, to do it for > you. > > Happy hacking, > > Moritz > > [1] http://en.wikipedia.org/wiki/Pragma_once > -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBAgAGBQJTCliDAAoJEAFxB7BbsDrLieEH/1a76Tckl2wxu7Km8C3pwT5q MkKlL0x9/z7NnxpKsiehHG3dQvE6w2Gt4VfS/CICDsVcU7jxYfVJHnOx7l+RLJ5w ipU9ICKImQa+2Hn5L/2PYvwpW0JrkivGntJeiCt2UGP+Z/rBNLwuHUtSs8BR0FHO uDCC8kvMIx9qUOBvNYwYAkRuXlFlxZHzpkNFfzzIK6gIMhN5mjRvKb93x3mJtfkd dJR85OtxaKVFAz8kD9LEeKDLPa6DQtatfp2m07ghAlhdhyPbX+vyzqEfHhVq2p0Z uDa3a5GqrWaA4hRn+Ypx6kB0gBN4nSycdM8cT3A5ad7cKf8jtarNOm1vYUhC/Ac= =/8RU -----END PGP SIGNATURE----- _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
