gcc49 vs gcc48

Ryan Schmidt ryandesign at macports.org
Tue Nov 18 08:01:25 PST 2014

On Nov 18, 2014, at 5:34 AM, René J.V. Bertin wrote:
> For those of us still using 10.6 (whether real or virtualised): is there an advantage of gcc49 over gcc48? I think I read something about better optimisation somewhere, but is that noticeable enough to warrant spending the time of building and installing gcc49? Would that at least give some advantage when there's a libgcc update because that's a subport of gcc49 nowadays? Is the compiler itself faster?

I don't know what changes have occurred between gcc48 and gcc49. You could consult the changelog. Note that we do have binary packages, so if you're using binaries on your system there wouldn't be any time spent building.

> And what about gcc48, will I be able to uninstall it without having to rebuild the ports I built with it, because that is apparently registered as a dependency nowadays? (kfilemetadata is among them, while according to the CMakeCache.txt file in the build dir that I kept, it's been built with Apple's clang 3.0 ...)

You can uninstall gcc48 if no installed ports declare library or runtime dependencies on it. Most ports that use gcc link with libgcc. Back when libgcc was part of each gcc port, other ports would declare library dependencies on the gcc port. Then we moved libgcc out into its own subport, so now ports that use gcc should usually declare a build dependency on the gcc port and a library dependency on the libgcc port. There may be some old ports that have not been updated for this.

There is no mention of any gcc dependency in the kfilemetadata port.

> BTW, I've noticed subtle but fatal issues with what I'll call header confusion between gcc-4.9 and clang-3.5 on Linux. I don't know about clang-3.4 (which I have and use in MacPorts) but I'd hate to bump into those on OS X too...

I'm not aware of this.

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