I recently had the need to install a newer version of the g++ compiler on Ubuntu 12.04 LTS. I documented the approach here.
Ubuntu does not typically release new toolchains for their stable versions, instead newer toolchains are made available in a PPA (Personal Package Archive) “https://launchpad.net/~ubuntu-toolchain-r/+archive/test“ to use the repository we can use the add-apt-repository command:
sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt-get update
sudo apt-get install gcc-4.7 g++-4.7
Currently the PPA contains gcc/g++-4.7 and 4.8. After installing one or multiple of the newer versions we can use update-alternatives to switch between the different versions. The update-alternatives tool manages symlinks to the different installed versions and allow us to easily switch between them.
Before we add the new gcc/g++ lets check if we already have any alternatives setup by running:
$ update-alternatives --display gcc
If you don’t have any alternatives installed it will just print:
update-alternatives: error: no alternatives for gcc.
Lets see how to add an alternative:
$ sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.7 60 --slave /usr/bin/g++ g++ /usr/bin/g++-4.7
$ sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.6 40 --slave /usr/bin/g++ g++ /usr/bin/g++-4.6
As a default when we install new alternatives they are added to a group (in this case gcc) in automatic mode. This means that the link with the highest priority will become the default. In the case above we gave gcc-4.7 a priority of 60 and gcc-4.6 a priority of 40, so the default with be gcc-4.7
The –slave options tells update-alternative that when we change gcc it should also update the g++ links.
To check that everything is ok or to switch between the compilers we can use
$ sudo update-alternatives --config gcc
There are 2 choices for the alternative gcc (providing /usr/bin/gcc).
Selection Path Priority Status
------------------------------------------------------------
* 0 /usr/bin/gcc-4.7 60 auto mode
1 /usr/bin/gcc-4.6 40 manual mode
2 /usr/bin/gcc-4.7 60 manual mode
Press enter to keep the current choice[*], or type selection number: 0
That is more or less it. Running gcc --version shows that we are now using the newer version:
gcc (Ubuntu/Linaro 4.7.3-2ubuntu1~12.04) 4.7.3
Copyright (C) 2012 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
I tried to use this method to install gcc-4.9 as you show above, but get:
$ sudo add-apt-repository ppa:ubuntu-toolchain-r/test
$ sudo apt-get update
$ sudo apt-get install gcc-4.9
Reading package lists… Done
Building dependency tree
Reading state information… Done
E: Unable to locate package gcc-4.9
E: Couldn’t find any package by regex ‘gcc-4.9’
When I look at the ppa site (your link above) it definitely has a gcc-4.9 entry.
Hi Phil, you are right for 12.04 gcc-4.9 is not available – only up until 4.8 seems to be available. I will edit the post.
Your post is very clear and saved me a lot of time.
Thanks a lot !
Agree! Cool, that you explaned what each command does.
I even learned some about update-alternatives.
Thank you very much, Morten.
Thanks mortenvp for this one. I needed the new gcc compiler for C++11 features. Thanks a lot!
I installed gcc-5 and g++-5 just now. It works for me.
sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt-get update
sudo apt-get install gcc-5 g++-5
Hello,
I installed version 4.8 on my Mint 13 (12.04 based). All was smooth, however when issuing g++ –version I still got 4.6.3 (previous installed version).
It turned out to be the symlink in /usr/bin that had to be directed to the newly installed gcc-4.8 and g++-4.8.
Not sure if you want to add this into control files or just leave a notice to users.
I see you installed gcc/g++ version 5. Have you done this on 12.04 too?
Thanks for sharing this PPA with us!
Best
Giampiero
thanks alot man .it worked
Works fine in 2017, saved me tons of time.
thanx a bunch