how to interpret messages with package dependencies problems using apt

Question

I'm having some problems to install some packages in a Debian box. The problem is more related with the error message interpretation. I'm trying to install the libssl-dev. So I fired a shell and I typed:

apt-get install libssl-dev

For my surprise i've got the following error:

libssl-dev: Depends: libssl0.9.8 (= 0.9.8o-4squeeze1) but 0.9.8o-6 is to be installed
E: Broken packages

So what exactly it means? It depends the libssl0.9.8 ( the squeeze1 version) but the 0.9.8o-6 will be installed? Is this minor number (the "o-6") a blocking for apt-get? Can I force it (I did try with the -f, but it didn't work)?

Answer 1

The version of libssl-dev that APT would install requires version 0.9.8o-4squeeze1 of libssl0.9.8. The equal sign means “exactly this version”. Version 0.9.8o-6 is different, so it's a no go.

Run apt-cache policy libssl-dev libssl0.9.8 to see what versions of these packages you have installed and what versions are available for installation. Post the output if you still need help.

If you meant to have a squeeze (stable) Debian, you shouldn't have -6 anywhere, so you have a spurious package source. If you meant to have a wheezy (testing) or sid (unstable) Debian, you either have incomplete sources, or need to refresh the list of available packages with apt-get update first.