Message 200507 - Python tracker (original) (raw)

I guess this should be clarified in the docs, but multiprocessing.pool.Pool is a class whose constructor takes a context argument, where as multiprocessing.Pool() is a bound method of the default context. (In previous versions multiprocessing.Pool was a function.)

The only reason you might need the context argument is if you have subclassed multiprocessing.pool.Pool.

from multiprocessing import pool, get_context forkserver = get_context('forkserver') p = forkserver.Pool() q = pool.Pool(context=forkserver) p, q (<multiprocessing.pool.Pool object at 0xb71f3eec>, <multiprocessing.pool.Pool object at 0xb6edb06c>)

I suppose we could just make the bound methods accept a context argument which (if not None) is used instead of self.