Update Gcc on Osx

Update GCC on OSX

If you install macports you can install gcc select, and then choose your gcc version.

/opt/local/bin/port install gcc_select

To see your versions use

port select --list gcc

To select a version use

sudo port select --set gcc gcc40

Installing GCC on macOS Catalina

Probably not the elegant answer, but it worked. I was able to find the header files needed using $(xcrun --show-sdk-path) I then copied them all to /usr/local where the gcc location was expecting them to be. Now all works.

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

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

Mac clang installation seems to override GCC install

Here are some simple truths, statements and observations to try and explain what's going on:

Apple ships the clang/LLVM compiler with macOS. Clang is a "front-end" that can parse C, C++ and Objective-C down to something that LLVM (referred to as a "back-end") can compile
Clang/LLVM is located in /Applications/Xcode.app/somewhere
Apple also ships a /usr/bin/gcc which just runs clang. I have no idea why they do that - it doesn't seem very helpful to me - but they don't answer my questions
Apple puts its binaries (programs) in /usr/bin. That is an integral part of macOS and you should never touch or change anything in there - you are asking for problems if you do. This warning applies to Python too.

If you want the real, lovely GNU Compiler Collection (GCC) which includes the gcc, g++ and gfortran compilers, your best bet, IMHO, is to get them from homebrew. I will not put the installation instructions here because they could become outdated, so you should use the ones on the homebrew site.

Once you have homebrew installed, you can install the GNU Compiler Collection (GCC) with:

brew install gcc

After that, you will have all the lovely GNU Compiler Collection (GCC) of tools in /usr/local/bin, so you should put that in your PATH, near the beginning, and in any case before /usr/bin, using:

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

In general, you should also add a similar line into your login profile, or into the system login profile, so it is set up every time you or any other user logs in.

Let's take a look:

ls /usr/local/bin/gcc* /usr/local/bin/g++*

/usr/local/bin/gcc-10
/usr/local/bin/g++-10

Depending on the versions and updates, you will then have these programs available:

gcc-10          # the real GNU C compiler
g++-10          # the real GNU C++compiler
gfortran        # GNU fortran compiler

And you can check their versions with:

gcc-10 -v
g++-10 -v
gfortran -v

Now you know about homebrew, here are some more simple truths and observations:

folks (who are not the supplier of the operating system) who supply binaries (programs) for you should put their stuff in /usr/local to show that it is just a locally installed program rather than a part of the core macOS operating system
homebrew is well-behaved and installs its binaries (programs) in /usr/local/Cellar and then usually makes symbolic links from /usr/local/bin/PROGRAM to the Cellar. None of this interferes with Apple-supplied stuff.
if you want to run the homebrew version of a command, you should have /usr/local/bin first on your PATH

Let's have a look at those symbolic links:

ls -l /usr/local/bin/g*10

lrwxr-xr-x  1 mark  admin  31 21 Aug 16:41 /usr/local/bin/g++-10 -> ../Cellar/gcc/10.2.0/bin/g++-10
lrwxr-xr-x  1 mark  admin  31 21 Aug 16:41 /usr/local/bin/gcc-10 -> ../Cellar/gcc/10.2.0/bin/gcc-10

If you want to know what you are actually running when you enter a command, use the type command like this.

type gcc
gcc is hashed (/usr/bin/gcc)

That tells you that if you run gcc you will actually be running /usr/bin/gcc which we know is from Apple - because it is in /usr/bin

Now try this:

type gcc-10
gcc-10 is hashed (/usr/local/bin/gcc-10)

That tells you that if you run gcc-10 you will actually be running /usr/local/bin/gcc-10 which we know is from homebrew - because it is in /usr/local/bin

Can't compile c++ program using gcc on Mac after updating to Monterey

I also had the same problem and in my case the problem was outdated
command line developer tools.

I found out it by running

$ brew doctor
...
Warning: Your Command Line Tools are too outdated.
Update them from Software Update in System Preferences or run:
  softwareupdate --all --install --force

If that doesn't show you any updates, run:
  sudo rm -rf /Library/Developer/CommandLineTools
  sudo xcode-select --install

Alternatively, manually download them from:
  https://developer.apple.com/download/all/.
You should download the Command Line Tools for Xcode 13.1.

I tried to update them via softwareupdate -l, however this did not give me any update information.

So removed them and reinstalled with xcode-select --install.

After this g++-11 stopped giving me an error about this header.

Now brew config tells me that I have CLT: 13.0.0.0.1.1627064638

P.S.

Also I started the xcode and it asked me whether additional components need to be installed and I said yes.

How do I upgrade gcc's Clang version in OS X?

Install Xcode, which will give you the latest available versions of both:

xcode-select --install
...

$ g++ --version
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 8.0.0 (clang-800.0.42.1)
Target: x86_64-apple-darwin16.4.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

$ clang --version
Apple LLVM version 8.0.0 (clang-800.0.42.1)
Target: x86_64-apple-darwin16.4.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin