Sharing User Library and Session between 2 applications

[eluser]WanWizard[/eluser]
Don't know exactly what you mean by 'sharing the user library'.

Are you talking about two separate CI applications (with their own applications directory) that are sharing the same database (otherwise you wouldn't be able to access the session)?

In CI 1.7.2, the only option is to have the library available in both applications. You can also use a modular solution, and load the user library from the module directory that both applications share. If you use CI 2.0, you can install the user library as a 3rd party library, and load it from both application by adding it as a package.