spawn launches a Python script in a new thread which will run concurrently with the PyMOL interpreter. It can be run in its own namespace (like a Python module, default), a local name space, or in the global namespace.
fork is an alias for spawn.
spawn python-script [, ( local | global | module | main | private )]
Not directly available. Instead, use cmd.do("spawn ...").
The default mode for spawn is "module".
Due to an idiosyncracy in Pickle, you can not pickle objects directly created at the main level in a script run as "module", (because the pickled object becomes dependent on that module). Workaround: delegate construction to an imported module.
The best way to spawn processes at startup is to use the -l option (see "help launching").