Section 1.3 in the Advanced Programming Guide, Threads and Concurrency, has information on what you can and can't do with multiple threads. Basically you can create multiple environments each running in its own thread, but you can't have multiple threads accessing a single environment.
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Can I call multiple threads from within one CLIPS program? If not, do you know of any multi-threaded versions of CLIPS?
Section 1.3 in the Advanced Programming Guide, Threads and Concurrency, has information on what you can and can't do with multiple threads. Basically you can create multiple environments each running in its own thread, but you can't have multiple threads accessing a single environment.