On Jan 13, 7:02 pm, Catherine Moroney <catherine.m.moro...@jpl.nasa.gov> wrote: > Hello everybody, > > I know how to spawn a sub-process and then wait until it > completes. I'm wondering if I can do the same thing with > a Python function. > > I would like to spawn off multiple instances of a function > and run them simultaneously and then wait until they all complete. > Currently I'm doing this by calling them as sub-processes > executable from the command-line. Is there a way of accomplishing > the same thing without having to make command-line executables > of the function call? > > I'm primarily concerned about code readability and ease of > programming. The code would look a lot prettier and be shorter > to boot if I could spawn off function calls rather than > subprocesses. > > Thanks for any advice, > > Catherine
'multiprocessing' does what you mentioned, as others said. The abstraction layer is solid, which makes your code pretty. However, it just creates a command line like this: '"c:\\programs\\python26\\python.exe" "-c" "from multiprocessing.forking import main; main()" "--multiprocessing-fork" "1916"' The handle '1916' is a pipe used to read further instructions. The arrive in 'main()' in the form of a pickled (serialized) dictionary. In it, the 'main_path' key contains the path to your program. 'main ()' calls the 'prepare()' function, which calls 'imp.find_module', using that path. Pretty sophisticated. You can do it yourself by creating your own command line. Create a subprocess by this command line (untested & lots of caveats): '"c:\\programs\\python26\\python.exe" "-c" "from myprogram import myfunc; myfunc()"' But you have practically no communication with it. If you need parameters, you can include them on the command line, since you're building it yourself (untested & highly vulnerable): '"c:\\programs\\python26\\python.exe" "-c" "from myprogram import myfunc; myfunc( literal1, literal2 )"' For a return value, unless it can be a simple exit code, you'll need a communication channel. For it, a socket wouldn't be bad, or a pipe if you're not on Windows (include the port or descriptor on the command line). (Even with 'multiprocessing', you're limited to pickleable objects, however, I believe.) -- http://mail.python.org/mailman/listinfo/python-list
