Embedded Python: Multiprocessing Not Working

I'm using Python 3.1.4 that is embedded as a scripting environment in an application(x64). So far I have encountered a lot of limitations with the embedded python. I don't know if

Solution 1:

By default, sys.argv is not available in embedded code:

Embedding Python

The basic initialization function is Py_Initialize(). This initializes the table of loaded modules, and creates the fundamental modules builtins, __main__, and sys. It also initializes the module search path (sys.path).

Py_Initialize() does not set the “script argument list” (sys.argv). If this variable is needed by Python code that will be executed later, it must be set explicitly with a call to PySys_SetArgvEx(argc, argv, updatepath) after the call to Py_Initialize()

On Windows, multiprocessing must spawn new processes from scratch. It uses a command line switch --multiprocessing-fork to distinguish child processes, and also transmits the original argv from parent to child.

Assigning sys.argv = ['c:/pathToScript/scipt.py'] before creating subprocesses, like you discovered, would seem to be a good workaround.

A second relevant piece of documentation is that of multiprocessing.set_executable():

Sets the path of the Python interpreter to use when starting a child process. (By default sys.executable is used). Embedders will probably need to do some thing like

set_executable(os.path.join(sys.exec_prefix, 'pythonw.exe')) before they can create child processes. (Windows only)