You want common, persistent memory across all processes? The Environment Variable suggestion is a good one, but if you need fast access to larger memory arrays it has its limits.
I don't know Mason, but IIWM, I'd use Shared Memory (SYSVSHM, in BSD parlance). Look up shmget, shmread, shmwrite. The tricky parts are:
- figuring out how to pass the memory pointer handle to each process
- write-locking the memory
I always write code for webservers I have control of (!), so I can usually simplify the first problem because I can force my allocation to occur before anyone else's, assuring me of a known location. However, if you can get your sysadmin to allow you to allocate a small known mailbox location as the first SHM allocation, then you can use that location as the place to store your application's larger variable array. Failing the availability of this, you can always use a file in a known location. Once this is cached, the performance hit isn't too bad.
SHM is a powerful tool!