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 of the interpreter, not the sys.argv which excludes options to the interpreter itself (like -m, -O, etc.).

sys.flags tells us which boolean options were set, but it doesn't tell us about -m arguments, and the set of flags is bound to change over time, creating a maintenance burden.

On Linux you can use procfs to retrieve the original command line, but this is not portable (and it's sort of gross):

open('/proc/{}/cmdline'.format(os.getpid())).read().split('\0')

Answer 1

You can use ctypes

~$ python2 -B -R -u
Python 2.7.9 (default, Dec 11 2014, 04:42:00) 
[GCC 4.9.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
Persistent session history and tab completion are enabled.
>>> import ctypes
>>> argv = ctypes.POINTER(ctypes.c_char_p)()
>>> argc = ctypes.c_int()
>>> ctypes.pythonapi.Py_GetArgcArgv(ctypes.byref(argc), ctypes.byref(argv))
1227013240
>>> argc.value
4
>>> argv[0]
'python2'
>>> argv[1]
'-B'
>>> argv[2]
'-R'
>>> argv[3]
'-u'