The Software Collections ( SCL ) Repository
参考：https://wiki.centos.org/AdditionalResources/Repositories/SCL

devtoolset-3 版本默认安装的是4.9.2，devtoolset-4 版本默认安装的是5.3版本，还可以往上类推。

CentOS 6/7 official support this. You don't need third party repository. And gcc version is 4.9.2 in CentOS's repo.

yum install centos-release-scl-rh
yum install devtoolset-3-gcc devtoolset-3-gcc-c++

To use the updated tools, start a new shell using the scl command:

scl enable devtoolset-3 bash

You may also need to reset your PATH environment variable, which might be set in ~/.bashrc or other profile file. If you need to change it, it should point to /opt/rh/devtoolset-3/root/usr/bin/:$PATH