Read from stdin in Python Process? -

i'm trying read sys.stdin inside of python process object, keep getting "valueerror: i/o operation on closed file" result. here's quick example:

import sys multiprocessing import process  def do_something(input_data):     x in input_data:         print x   input=sys.stdin  p = process(target=do_something, args=(input,)) p.start()  p.join() #wait process complete  

the above script fails with:

traceback (most recent call last):   file "/usr/local/cellar/python/2.7.5/frameworks/python.framework/versions/2.7/lib/python2.7/multiprocessing/process.py", line 258, in _bootstrap     self.run()   file "/usr/local/cellar/python/2.7.5/frameworks/python.framework/versions/2.7/lib/python2.7/multiprocessing/process.py", line 114, in run     self._target(*self._args, **self._kwargs)   file "example.py", line 6, in do_something     x in input_data: valueerror: i/o operation on closed file 

just calling do_something(input) works fine without using process, of course. creating pipe() object seems - can write contents of stdin pipe , results in string form within process - need input file-like form downstream operations. dump contents file , re-read in within process, seems pretty clumsy, if stdin big. there easy way read sys.stdin within process?

this because before process started, stdin closed. otherwise happen both parent , child process (or multiple child processes) try read same stdin, bad idea.

in child process sys.stdin redirected /dev/null:

from multiprocessing import process import sys  def test(*args):     print(args)     print(sys.stdin, sys.stdin.fileno())  if __name__ == '__main__':     p = process(target=test, args=(sys.stdin,))     p.start()     p.join() 

should print similar this:

(<closed file '<stdin>', mode 'r' @ 0x7f3b4564b0c0>,) (<open file '/dev/null', mode 'r' @ 0x7f3b43a9e0c0>, 3) 

the passed argument here reference closed file object, trying use raise error you've seen.

you around using os.dup() on sys.stdin.fileno() in parent , pass returned copy of file descriptor child argument, can use os.fdopen() work it.

the cleaner solution read input in parent process , pass child using multiprocessing.queue.