Updating Apple g++/gcc

What is the difference between Apple gcc and GNU gcc? Is Apple gcc a superset of the standard one?

The g++ version information in my OSX shows:

$ g++ --version
i686-apple-darwin11-llvm-g++-4.2 (GCC) 4.2.1 (Based o开发者_StackOverflown Apple Inc. build 5658) (LLVM build 2335.15.00)

Some of the latest features of C++11 are in gcc 4.3/4.4 as per this. Is there any newer version of Apple gcc I can upgrade to. if so, how can i do it? I have Xcode 4.1

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Well, for the first part, Apple in this case is using the LLVM backend for g++ as the default g++. Apple also installs the wonderfully named clang and clang++ front-ends for LLVM. However, there is absolutely nothing stopping you from installing newer branches of GCC; MacPorts has packages for everything up to 4.6. If you look for "APPLE ONLY" in the gcc man page, you can see what won't be available outside of Apple branches.

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Beside the already mentioned llvm-gcc and clang, there is also an Apple-supplied gcc-4.2 (without LLVM backend) at /usr/bin/gcc-4.2 in Xcode 4.1. But do not overwrite the Apple-supplied versions in /usr/bin. All three support a superset of features include multi-arch support and multi-abi support not found in the vanilla GNU distributions and many third-party packages depend on these features in OS X. If you install something via MacPorts or from source, it will be installed to a different path, like /opt/local/bin or /usr/local/bin. Use PATHs or environment variables to manage which compiler you use.

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You can use macport to install newer versions. You can download it here. Once you have installed gcc with macport, you can use it with xcode by adding an user-defined setting to your build :

- Go to the build setting of your project
- Click on the add build setting button
- Choose user-defined setting
- Name it CC
- In the value field, put the path of the gcc version installed by macport.

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One thing that definitely is present in the Apple GCC branch but not in GNU GCC is blocks.