=== Default gcc is version 4.4.7 ===

Centos 6 only support devtools with gcc/g++ 4.4.7

To see which version of gcc tools are set for your environment:

  gcc --version

=== Software Collections ===

To install and use other versions, we use Software Collections. This provides a way to easily set up your environment to use a particular version of software that's not installed in a standard location.

The gcc collections below are available both on ''chead'' and on the nodes.

To see everything available with scl (Software Collections)

  scl -l 

To use a Software Collection, you invoke the ''scl'' command like below:

=== gcc 4.8.2 ===
devtools-2 has been installed and includes gcc 4.8.2.
To use it, run this command to enable it for your current login

  scl enable devtoolset-2 bash

This will start a new shell that's set up for gcc 4.8.2. Run ''gcc --version'' to verify.

=== gcc 4.9.1 ===
devtools-3 has been installed and includes gcc 4.9.1.
To use it, run this command to enable it for your current login

  scl enable devtoolset-3 bash

=== Alternately ===

For either version you can:

  export CC=/opt/rh/devtoolset-[2 or 3]/root/usr/bin/gcc  
  export CPP=/opt/rh/devtoolset-[2 or 3]/root/usr/bin/cpp
  export CXX=/opt/rh/devtoolset-[2 or 3]/root/usr/bin/c++