Perl in a Nutshell, 2nd Edition

Session and Cache Managers

The CPAN module contains a session manager, which keeps track of objects that have been fetched, built, and installed in the current session. No status is retained between sessions.

There is also a cache manager, which keeps track of disk space used and deletes extra space. The cache manager keeps track of the build directory, $CPAN::Config->{build_dir}, and uses a simple FIFO mechanism to delete directories below build_dir when they grow bigger than $CPAN::Config->{build_cache}.

The original distribution files are kept in the directory $CPAN::Config->{keep_source_where}. This directory is not covered by the cache manager but must be controlled by the user. If the same directory is used as both build_dir and keep_source_where, your sources are deleted with the same FIFO mechanism.