Error installing lib on Ubuntu

Question

when running the command sudo apt-get install libstdc++ I get the following output on Ubuntu:

libstdc++6 is already the newest version.
libstdc++6-4.6-dev is already the newest version.
libstdc++6-4.6-dev set to manually installed.
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

    The following packages have unmet dependencies:
     libstdc++6-4.5-dbg : Conflicts: libstdc++6-4.4-dbg but 4.4.7-1ubuntu2 is to be installed
     libstdc++6-4.5-dbg-armel-cross : Conflicts: libstdc++6-4.4-dbg-armel-cross but 4.4.7-1ubuntu2cross1.52 is to be installed
 libstdc++6-4.5-dbg-armhf-cross : Conflicts: libstdc++6-4.4-dbg-armhf-cross but 4.4.7-1ubuntu2cross1.52 is to be installed
 libstdc++6-4.5-doc : Conflicts: libstdc++6-4.4-doc but 4.4.7-1ubuntu2 is to be installed
 libstdc++6-4.6-dbg : Conflicts: libstdc++6-4.4-dbg but 4.4.7-1ubuntu2 is to be installed
                      Conflicts: libstdc++6-4.5-dbg but 4.5.3-12ubuntu2 is to be installed
 libstdc++6-4.6-dbg-armel-cross : Conflicts: libstdc++6-4.4-dbg-armel-cross but 4.4.7-1ubuntu2cross1.52 is to be installed
                                  Conflicts: libstdc++6-4.5-dbg-armel-cross but 4.5.3-12ubuntu2cross1.61 is to be installed
 libstdc++6-4.6-dbg-armhf-cross : Conflicts: libstdc++6-4.4-dbg-armhf-cross but 4.4.7-1ubuntu2cross1.52 is to be installed
                                  Conflicts: libstdc++6-4.5-dbg-armhf-cross but 4.5.3-12ubuntu2cross1.61 is to be installed
 libstdc++6-4.6-doc : Conflicts: libstdc++6-4.4-doc but 4.4.7-1ubuntu2 is to be installed
                      Conflicts: libstdc++6-4.5-doc but 4.5.3-12ubuntu2 is to be installed
E: Unable to correct problems, you have held broken packages.

I have already run the showhold command (apt-mark showhold) - nothing is held.

How can I resolve conflicts like these 4.4.7-1ubuntu2 is to be installed?

Thank you Thomas

Answer 1

The package in question happens to be installed already.

libstdc++6 is already the newest version.
libstdc++6-4.6-dev is already the newest version.
libstdc++6-4.6-dev set to manually installed.

Merely typing apt-get install libstdc++ will try to install every version of libstdc++ out there on the package manager (6.4.5 docs/debug, while the current version is in fact 6.4.6) so you should be specific about which package you want to install:

# apt-get install libstdc++6