Open file with mmap fails

Question

Python 2.7 on Windows. Trying to use mmap module, but use open file handler instead of with open(filename, "r+b") as f: I just open it and get an WindowsError [Error 5].

It does reproduce, either run as Administrator or not. Using codecs.open() doesn't resolve the problem.

# -*- coding: utf8 -*-
from __future__ import print_function
import mmap

class QSHFile(object):
    def __init__(self, filename):
        self.filename = filename
        self.file = open(filename, 'r')
        self.fileno = self.file.fileno()
        self.mm = mmap.mmap(self.fileno, 0)
        print(self.mm[:5])  # prints first 5


if __name__ == '__main__':
    qsh = QSHFile('example.qsh')

After a bit or research, I came into:

#! /usr/bin/python
# -*- coding: utf8 -*-
from __future__ import print_function
from mmap import ACCESS_READ, mmap

class QSHFile(object):
    def __init__(self, filename):
        self.filename = filename
        self.file = open(filename, 'rb')
        self.fileno = self.file.fileno()
        self.mm = mmap(self.fileno, 0, access=ACCESS_READ)
        print(self.mm[:5])

if __name__ == '__main__':
    qsh = QSHFile('example.qsh')

And now it's working fine. Am I doing correct now?

Answer 1

Yes, that's it, thanks to everyone!

# -*- coding: utf8 -*-
from __future__ import print_function
from mmap import ACCESS_READ, mmap
from binascii import hexlify as hex

class QSHFile(object):
    def __init__(self, filename):
        self.filename = filename
        self.file = open(filename, 'rb')
        print('File [%s] opened' % self.filename)
        self.fileno = self.file.fileno()
        self.mm = mmap(self.fileno, 0, access=ACCESS_READ)
        print('File size: %s bytes' % self.mm.size())
        print(hex(self.mm[:5]))


if __name__ == '__main__':
    qsh = QSHFile('example.qsh')