How to Install GCC Compiler on Ubuntu 18.04
This section provides instructions about how to install and use multiple versions of GCC on Ubuntu 18.04. The newer versions of the GCC compiler include support for new languages, better performance and extended features.
At the time of writing this article, the default Ubuntu repositories include several GCC versions, from 5.x.x to 8.x.x. The latest version of GCC, which is 9.1.0 is available from the Ubuntu Toolchain PPA.
In the following example, we will install the latest three versions of GCC and G++.
First, add the ubuntu-toolchain-r/test PPA to your system with:
sudo apt install software-properties-common
sudo add-apt-repository ppa:ubuntu-toolchain-r/test
Install the desired GCC and G++ versions by typing:
sudo apt install gcc-7 g++-7 gcc-8 g++-8 gcc-9 g++-9
The commands below will configure alternative for each version and associate a priority with it. The default version is the one with the highest priority, in our case that is gcc-9.
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-9 90 --slave /usr/bin/g++ g++ /usr/bin/g++-9 --slave /usr/bin/gcov gcov /usr/bin/gcov-9
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-8 80 --slave /usr/bin/g++ g++ /usr/bin/g++-8 --slave /usr/bin/gcov gcov /usr/bin/gcov-8
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-7 70 --slave /usr/bin/g++ g++ /usr/bin/g++-7 --slave /usr/bin/gcov gcov /usr/bin/gcov-7
Later if you want to change the default version use the update-alternatives command:
sudo update-alternatives --config gcc
There are 3 choices for the alternative gcc (providing /usr/bin/gcc).
Selection Path Priority Status
------------------------------------------------------------
* 0 /usr/bin/gcc-9 90 auto mode
1 /usr/bin/gcc-7 70 manual mode
2 /usr/bin/gcc-8 80 manual mode
3 /usr/bin/gcc-9 90 manual mode
Press to keep the current choice[*], or type selection number:
You will be presented with a list of all installed GCC versions on your Ubuntu system. Enter the number of the version you want to be used as a default and press Enter.
The command will create symbolic links to the specific versions of GCC and G++.