Osx - Replace Gcc Version 4.2.1 with 4.9 Installed via Homebrew

OSX - replace gcc version 4.2.1 with 4.9 installed via Homebrew

By default, homebrew places the executables (binaries) for the packages it installs into /usr/local/bin - which is a pretty sensible place for binaries installed by local users when you think about it - compared to /bin which houses standardisded binaries belonging to the core OS. So, your brew command should have installed gcc-4.9 into /usr/local/bin. The question is now how to use it... you have several options.

Option 1

If you just want to compile one or two things today and tomorrow, and then probably not use the compiler again, you may as well just invoke the gcc installed by homebrew with the full path like this:

/usr/local/bin/gcc-4.9 --version

Option 2

If you are going to be using gcc quite a lot, it gets a bit tiresome explicitly typing the full path every time, so you could put the following into your ~/.bash_profile

export PATH=/usr/local/bin:$PATH

and then start a new Terminal and it will know it needs to look in /usr/local/bin, so you will be able to get away with simply typing

gcc-4.9 --version

Option 3

If you just want to use gcc to invoke the compiler, without worrying about the actual version, you can do Option 2 above and additionally create a symbolic link like this

cd /usr/local/bin
ln -s  gcc-4.9  gcc

That will allow you to run the homebrew-installed gcc by simply typing gcc at the command line, like this

gcc --version

Note:

If you later want to install, say gcc-4.13 or somesuch, you would do your brew install as before, then change the symbolic link like this:

cd /usr/local/bin
rm gcc               # remove old link from gcc to gcc-4.9
ln -s gcc-4.13 gcc   # make new link from gcc to gcc-4.13

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Note that if you are actually using C++ rather than C, you will need to adapt the above for g++ in place of gcc.

gcc version showing 4.2.1 even after installing 4.9 (Homebrew)

homebrew installs gcc with version specific suffixes, so when you install gcc49, it gets called gcc-4.9 on the command line. This is intended to prevent interference with the gcc stub (which is actually clang) which is provided by the OSX command line development toolchain, as well as to allow you to install gcc-4.8, gcc-4.7, etc. alongside each other.

Generally defining the environment variables CC=gcc-4.9 and CXX=g++-4.9 should allow you to compile autoconf based packages, as well as standard makefile based projects using the gcc-4.9 compiler, rather than using the default cc/gcc.

How can I install gcc 4.2.1 on OSX Sierra?

You can install previous version of gcc pretty easily using homebrew.

If you have homebrew installed you can get gcc 4.9 by running

brew install gcc@4.9

After it is installed gcc will still map to the clang that came with your mac. The newly installed gcc will be installed at /usr/local/bin and be called something like gcc-4.

You can find the exact executable name using

ls /usr/local/bin | grep gcc

Hopefully 4.9 is close enough to 4.6 for your purposes.

Mac OS X: Installed and linked gcc 6.2 with Homebrew, but gcc --version still says 4.9.2

You created the symlink with the proper target name (gcc) but forgot to set the PATH to your newly installed location (or set it after the system path).

What's confusing is that your system already has a version of gcc installed. You have to override the default path so your gcc command comes first.

• edit your ~/.profile file and check PATH adjustment. Add a line in the end which contains:

  export PATH=/usr/local/Cellar/gcc/6.2.0/bin:$PATH

Then open a new terminal and ensure that which gcc prints

/usr/local/Cellar/gcc/6.2.0/bin/gcc

Using Homebrew with alternate GCC

These answers are all fairly old now. It seems that recent versions of homebrew have a '--cc' option that enables you to select the c compiler to use. For example

brew install --cc=gcc-6 <package-name>

will install using the brew version of gcc

GCC on Mac OSX--multiple versions of gcc

By default, your gcc installations should be in /usr/bin/. So, for example, to use gcc 4.2, you'd use /usr/bin/gcc-4.2 to compile your files. You can do ls /usr/bin/gcc* to see which ones you have installed.

EDIT:
If gcc isn't installed in the default path (i.e., /usr/bin/), then you can execute locate gcc in the terminal to find where it is located.

gcc installed via homebrew doesn't have manpages

Homebrew doesn't like using the names gcc and g++, since they're already in use by the operating system, and will refuse to link to gcc and g++. Instead it links gcc-4.9 and g++-4.9.

In the same way, you can access the manpages with man gcc-4.9 rather than man gcc and man g++-4.9 rather than man g++.

Mac OSX is using gcc 6.2.0 but g++ 4.9.2

I had to do this:

cd /usr/local/Cellar/gcc/6.2.0/bin/gcc

ln -s g++-6 g++

which I guess I had previously done for gcc.

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