package g++ 4:5.3.1-1ubuntu1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 2

[Shahram Bekhrad]

I have had installed the latest version of gcc (gcc-6 and g++-6) from ppa:ubuntu-toolchaint-r/test.
It was running as beautifully and smoothly as possible. But I think after a automatic system update on Ubuntu Software, it has a problem and my IDE (Code::Blocks) couldn't find the binary file for g++ or gcc.

I tried the command:

ls -l cpp* gcc* g++*

as root in the /usr/bin directory but no such file exist which is contrary to what

locate gcc

command reports.

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: g++ 4:5.3.1-1ubuntu1
ProcVersionSignature: Ubuntu 4.4.0-24.43-generic 4.4.10
Uname: Linux 4.4.0-24-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
Date: Wed Jun 22 15:01:52 2016
DuplicateSignature:
 package:g++:4:5.3.1-1ubuntu1
 Setting up g++ (4:5.3.1-1ubuntu1) ...
 update-alternatives: error: alternative path /usr/bin/g++ doesn't exist
 dpkg: error processing package g++ (--configure):
  subprocess installed post-installation script returned error exit status 2
ErrorMessage: subprocess installed post-installation script returned error exit status 2
InstallationDate: Installed on 2016-06-11 (11 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.1
 apt 1.2.10ubuntu1
SourcePackage: gcc-defaults
Title: package g++ 4:5.3.1-1ubuntu1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 2
UpgradeStatus: No upgrade log present (probably fresh install)

[Matthias Klose (doko)]

Setting up g++ (4:5.3.1-1ubuntu1) ...
update-alternatives: error: alternative path /usr/bin/g++ doesn't exist
dpkg: error processing package g++ (--configure):
 subprocess installed post-installation script returned error exit status 2

apparently some local change handling the /usr/bin/g++ symlink with update-alternatives. don't do that.