How to install older gcc package using APT from a repository? - linux

Question

I have GCC v9. But I'm trying to install a GCC 4.8.1 version to test a library compilation on that very old version of GCC.
The version is not available in the official Ubuntu repos,it is deprecated, but I've found it in other mirrors as told by the official GCC website. This one seems like popular one:
https://launchpad.net/~ubuntu-toolchain-r/+archive/ubuntu/test
I have very little knowledge of linux package systems except for the basic. I want to keep both versions. So I should do this:
sudo apt -y install gcc-4.8.1 gcc-9
The reason why I want to use this command and not install it from the file, apart from the difficulty of doing that for me, is that I'm following a guide in order to have several GCCs on my system:
https://www.fosslinux.com/39386/how-to-install-multiple-versions-of-gcc-and-g-on-ubuntu-20-04.htm
When I add the url to the sources.list file seems like it is working.
sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt update -q
But when I try to call the install with gcc-4.8.1 or gcc-4.8 , or even gcc-4 the package doesn't exist.
Package gcc-4.8 is not available, but is referred to by another
package. This may mean that the package is missing, has been
obsoleted, or is only available from another source E: Package
'gcc-4.8' has no installation candidate
Also, I don't know if websites like these can be added to the repos list in order to find the package using APT:
http://www.netgull.com/gcc/releases/gcc-4.8.1/
[EDIT]
I downloaded the package from the website I linked. I have no idea how to install this by hand. If only I could find a repository that could help me with this... I have no idea how to make APT help me with the installation.

Answer 1

But I'm trying to install a GCC 4.8.1 version to test a library compilation on that very old version of GCC.
Developers have tools up their sleeve so they don't have to install dependencies and bloating their systems for every library (and every configuration of that library!) they want to try out and test.
Use docker. You could write for example a testing script, assuming your project uses make:
# test_my_lib_in_gcc-4.8.sh
#!/bin/sh
docker run -ti --rm -v $PWD:/project -w /project gcc:4.8 -u $UID:$GID sh <<EOF
make && make test
EOF
that will compile and test your application in using 4.8 gcc. Consider how easy it is to change gcc version - just change the number. You could test your library in gcc, in different versions, and using other compilers and on different distributions to make sure it works for others. If you're a developer of the library, write an automatized CI pipeline that would automatically test your application each commit in specific docker environment, using ex. https://docs.gitlab.com/ee/ci/README.html or https://travis-ci.org/ .