473,320 Members | 1,713 Online
Bytes | Software Development & Data Engineering Community
Post Job

Home Posts Topics Members FAQ

Join Bytes to post your question to a community of 473,320 software developers and data experts.

Cross-platform issues with file's a+ mode

I was helping someone debug his code today .. it worked fine on Linux, but
gave a strange error message on Windows. Here's the snippet that goes
wrong in Python 2.2 under Windows (it also happens under 2.3a1 under
Windows and Enthought's 2.3.3, so I think it's pretty generic) .. :
os.remove('test.txt')
f = file('test.txt','a+')
f.readline() '' f.write('beep') Traceback (most recent call last):
File "<pyshell#48>", line 1, in ?
f.write('beep')
IOError: (0, 'Error')

but .. I can make things work by seeking:
f.seek(0)
f.write('beep')

I don't know whether it's important or not, but if I do an f.tell() after
the readline(), it says 0L, which seems reasonable.

For comparison (and this is also true under, e.g., Linux 2.3a1),

bash-2.04$ python
Python 2.2 (#1, Feb 18 2002, 14:48:51) [C] on sunos5
Type "help", "copyright", "credits" or "license" for more information. import os
os.remove('test.txt')
f = file('test.txt','a+')
f.readline() '' f.write('beep')


What's going on here? Should I expect this behavior? I've never needed
to use a+ mode before .. is it just known to be funny or have interesting
cross-platform issues?

Thanks,

-michael
Jul 18 '05 #1
0 1122

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

0
by: Web Science | last post by:
Site and Features: http://www.eigensearch.com Search engine, eigenMethod, eigenvector, mathematical, manifolds, science, technical, search tools, eigenmath, Jacobian, quantum, mechanics,...
0
by: Web Science | last post by:
Site and Features: http://www.eigensearch.com Search engine, eigenMethod, eigenvector, mathematical, manifolds, science, technical, search tools, eigenmath, Jacobian, quantum, mechanics,...
4
by: David Peach | last post by:
Hello, hope somebody here can help me... I have a query that lists defects recorded in a user defined date range. That query is then used as the source for a Cross Tab query that cross-tabs count...
23
by: Jeff Rodriguez | last post by:
Here's what I want do: Have a main daemon which starts up several threads in a Boss-Queue structure. From those threads, I want them all to sit and watch a queue. Once an entry goes into the...
0
by: Web Science | last post by:
Site and Features: http://www.eigensearch.com Search engine, eigenMethod, eigenvector, mathematical, manifolds, science, technical, search tools, eigenmath, Jacobian, quantum, mechanics,...
7
by: Scott M. | last post by:
How can I disable the cross-site scripting check for one particular page of a site?
8
by: Pieter | last post by:
Hi, I'm having some weird problem using the BackGroundWorker in an Outlook (2003) Add-In, with VB.NET 2005: I'm using the BackGroundWorker to get the info of some mailitems, and after each item...
1
by: Rob Woodworth | last post by:
Hi, I'm having serious problems getting my report to work. I need to generate a timesheet report which will contain info for one employee between certain dates (one week's worth of dates). I...
6
by: Bart Van der Donck | last post by:
Hello, I'm presenting my new library 'AJAX Cross Domain' - a javascript extension that allows to perform cross-domain AJAX requests. http://www.ajax-cross-domain.com/ Any comments or...
6
by: ampo | last post by:
Hello. Can anyone help with cross-domain problem? I have HTML page from server1 that send xmlHTTPRequest to server2. How can I do it? Thanks.
0
by: ryjfgjl | last post by:
ExcelToDatabase: batch import excel into database automatically...
0
by: Vimpel783 | last post by:
Hello! Guys, I found this code on the Internet, but I need to modify it a little. It works well, the problem is this: Data is sent from only one cell, in this case B5, but it is necessary that data...
0
by: ArrayDB | last post by:
The error message I've encountered is; ERROR:root:Error generating model response: exception: access violation writing 0x0000000000005140, which seems to be indicative of an access violation...
1
by: CloudSolutions | last post by:
Introduction: For many beginners and individual users, requiring a credit card and email registration may pose a barrier when starting to use cloud servers. However, some cloud server providers now...
1
by: Defcon1945 | last post by:
I'm trying to learn Python using Pycharm but import shutil doesn't work
1
by: Shællîpôpï 09 | last post by:
If u are using a keypad phone, how do u turn on JavaScript, to access features like WhatsApp, Facebook, Instagram....
0
by: af34tf | last post by:
Hi Guys, I have a domain whose name is BytesLimited.com, and I want to sell it. Does anyone know about platforms that allow me to list my domain in auction for free. Thank you
0
by: Faith0G | last post by:
I am starting a new it consulting business and it's been a while since I setup a new website. Is wordpress still the best web based software for hosting a 5 page website? The webpages will be...
0
isladogs
by: isladogs | last post by:
The next Access Europe User Group meeting will be on Wednesday 3 Apr 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM). In this session, we are pleased to welcome former...

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.