Never used them myself, but a CPAN search for shared cache brings up a number of promising looking modules, including IPC::SharedCache and Cache::FastMmap. The documentation from Cache::FastMmap says:
It uses fcntl locking to ensure multiple processes can safely access the cache at the same time.
so it should certainly be thread-safe.

In reply to Re: thread-safe mmap module ? by kennethk
in thread thread-safe mmap module ? by jdd

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