devtoolset-7 also provides newer versions of lots of supporting debug and performance tools like gdb.

They (RH or Centos) also provide containerised versions of the build tools and the performance tools.

There is also a tech preview of the llvm-toolset, admittedly at clang v4 but still able to build those compatible binaries.

Note that you want to build using a host that is lower or same version as your minimum target version.

e.g. toolset-7 on host centos v6.7 will create bins compatible with 6.7, 6.9 and 7.x If your host is say centos 7.2 toolset-7 builds are only guaranteed to be compatible with v7.2+ targets.

Redhat's documentation is really good (and you can even get a free developer login to access more resources).

Also note that Centos provides similar options to RHEL.

The only downside is I don't think you can use the new ABI variant of CXX LIB as the ABI isn't compatible with older compilers like the default Centos gcc 4

Not really a problem as you can still use the C++11/14/17 features, just a few items are incompatible (such as list::size() still being O(n) and not const time, or strings still being COW)

https://www.softwarecollections.org/en/scls/rhscl/devtoolset-7/ (Lots of other tools/langs etc there too like Go,Rust,Python3 and lots of database updated versions etc.)

Not sure if you need to have a developer account, but an example of the documentation: https://access.redhat.com/documentation/en-us/red_hat_developer_toolset/7/html/7.0_release_notes/dts7.0_release

An alternative of source /opt/rh/devtoolset-4/enable is

source scl_source enable devtoolset-4

The above shell script scl_source is more elegant than using a hard coded path (may be different on another machine). However scl_source does less because /opt/rh/devtoolset-4/enable uses scl_source and other stuff.

To use scl_source you may have to upgrade package scl-utils

yum update scl-utils  # old scl-utils versions miss scl_source

Quick copy-paste

echo 'source scl_source enable devtoolset-4' >> ~/.bashrc
    # Do not forget to change the version ↑

Source code for curious people

An example of scl_source source code:
https://gist.github.com/bkabrda/6435016

The scl_source installed on my Red Hat 7.1

#!/bin/bash

_scl_source_help="Usage: source scl_source <action> [<collection> ...]

Don't use this script outside of SCL scriptlets!

Options:
    -h, --help    display this help and exit"

if [ $# -eq 0 -o $1 = "-h" -o $1 = "--help" ]; then
    echo "$_scl_source_help"
    return 0
fi


if [ -z "$_recursion" ]; then
    _recursion="false"
fi
if [ -z "$_scl_scriptlet_name" ]; then
    # The only allowed action in the case of recursion is the same
    # as was the original
    _scl_scriptlet_name=$1
fi
shift 1

if [ -z "$_scl_dir" ]; then
    # No need to re-define the directory twice
    _scl_dir=/etc/scl/conf
    if [ ! -e $_scl_dir ]; then
        _scl_dir=/etc/scl/prefixes
    fi
fi

for arg in "$@"; do
    _scl_prefix_file=$_scl_dir/$arg
    _scl_prefix=`cat $_scl_prefix_file 2> /dev/null`
    if [ $? -ne 0 ]; then
        echo "Can't read $_scl_prefix_file, $arg is probably not installed."
        return 1
    fi

    # First check if the collection is already in the list
    # of collections to be enabled
    for scl in ${_scls[@]}; do
        if [ scl ]; then
            continue 2
        fi
    done

    # Now check if the collection isn't already enabled
    /usr/bin/scl_enabled $arg > /dev/null 2> /dev/null
    if [ $? -ne 0 ]; then
        _scls+=($arg)
        _scl_prefixes+=($_scl_prefix)
    fi;
done

if [ $_recursion == "false" ]; then
    _i=0
    _recursion="true"
    while [ {#_scls[@]} ]; do
        _scl_scriptlet_path="${_scl_prefixes[$_i]}/${_scls[$_i]}/${_scl_scriptlet_name}"
        source "$_scl_scriptlet_path"
        if [ $? -ne 0 ]; then
            echo "Can't source $_scl_scriptlet_name, skipping."
        else
            export X_SCLS="${_scls[$_i]} $X_SCLS"
        fi;
        _i=_i+1))
    done
    _scls=()
    _scl_prefixes=()
    _scl_scriptlet_name=""
    _recursion="false"
fi

It is because of your settings in .bashrc and/or .bash_profile. scl appends its path to gcc7 before starting your new bash shell, but the path to gcc is default to the old gcc4 again because your .bashrc appends /usr/bin to the path when starting the new bash, and it supersedes the scl settings. The solution is to use the "enable" script directly. That way no further path settings annoy you.

I ran into the same issue that you are facing and this is how I got it fixed:

1. Just want to be careful, you need to exist the Terminal and open a fresh one to start. This way, you are not under any devtoolset's bash.
2. Go to /opt/rh folder, run command ls -la to see if you have any devtoolset-* folder there. Let's say you have devtoolset-8, proceed step 2.
3. Go to /etc/scl/prefixes folder, if you don't see devtoolset-8 file, you can create a new one as devtoolset-8, and type 1 line: /opt/rh, then save and quit that file.
4. Once you are done, you can call: scl enable devtoolset-8 -- bash w/o any error. Good luck

devtoolset-8 was only released a short while ago. The linked installation instructions may be of use. However, your question pertains to CentOS, and this does not yet appear to have been made available yet. You can see some evidence of it being build for CentOS here, but it's not been updated for the final release yet.

You could ask on the SCL mailing list for an ETA, or wait until it appears in its final form. In the meantime, you could download the RPMs from koji directly.