Two processes reading/writing to the same file Python

Question

I have one process who's reading from a file (using file.read()) and one process who's writing to the same file (file.write()). The problem is it doesn't work - I get no errors but they can't operate at the same time. I've tried making the read and write operations none-blocking and then flushing the stream, as follows:

fcntl.fcntl(file, fcntl.F_SETFL, os.O_NONBLOCK) file.write(msg) file.flush() 

Am I completely misunderstanding it? How should one accomplish writing and reading to one file from different processes?

Answer 1

test1.py

import os f = open('txt.txt', 'a', os.O_NONBLOCK) while 1:         f.write('asd')         f.flush() 

test2.py

import os f = open('txt.txt', 'r', os.O_NONBLOCK) while 1:     print f.read(3) 

This works fine for me.

Answer 2

Is there a reason to use a common file? Inter-process communication is probably much easier using sockets.