Retrieve the command line arguments of the Python interpreter

Question

Inspired by another question here, I would like to retrieve the Python interpreter\'s full command line in a portable way. That is, I want to get the original argv

Answer 1

I'm going to add another answer to this. @bav had the right answer for Python 2.7, but it breaks in Python 3 as @szmoore points out (not just 3.7). The code below, however, will work in both Python 2 and Python 3 (the key to that is c_wchar_p in Python 3 instead of c_char_p in Python 2) and will properly convert the argv into a Python list so that it's safe to use in other Python code without segfaulting:

def get_python_interpreter_arguments():
    argc = ctypes.c_int()
    argv = ctypes.POINTER(ctypes.c_wchar_p if sys.version_info >= (3, ) else ctypes.c_char_p)()
    ctypes.pythonapi.Py_GetArgcArgv(ctypes.byref(argc), ctypes.byref(argv))

    # Ctypes are weird. They can't be used in list comprehensions, you can't use `in` with them, and you can't
    # use a for-each loop on them. We have to do an old-school for-i loop.
    arguments = list()
    for i in range(argc.value - len(sys.argv) + 1):
        arguments.append(argv[i])

    return arguments

You'll notice that it also returns only the interpreter arguments and excludes the augments found in sys.argv. You can eliminate this behavior by removing - len(sys.argv) + 1.