[Python-bugs-list] [ python-Bugs-756104 ] Calling socket.recv() with a large number breaks

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Bugs item #756104, was opened at 2003-06-17 14:25
Message generated for change (Comment added) made by tim_one
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=105470&aid=756104&group_id=5470

Category: Python Library
Group: Python 2.2.2
Status: Open
Resolution: None
Priority: 5
Submitted By: Alex R.M. Turner (plexq)
Assigned to: Nobody/Anonymous (nobody)
Summary: Calling socket.recv() with a large number breaks

Initial Comment:
I have a backup script that calls socket.recv() passing
the amount of data that is left to get for a given file
as the argument.  For very large files (I have one here
that is 1.9Gig) it seems to break horribly after
receiving about 130Meg.  I have tried to track it down
precisely with basic debugging (putting in print
statements in the python code) but it just seams to
freak out around the 130meg mark, and it just doesn't
make sense.  If I change the argument passed to recv to
32767 it works just fine.  I have attatched the loop
that reads data from the socket (In a working state,
the bad code is commented out).

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>Comment By: Tim Peters (tim_one)
Date: 2003-06-18 12:29

Message:
Logged In: YES 
user_id=31435

BTW, if you're new to socket programming, do read Python's 
socket programming HOWTO:

http://www.amk.ca/python/howto/sockets/

I expect you're the only person in history to try passing such 
a large value to recv() -- even if it worked, you'd almost 
certainly run out of memory trying to allocate buffer space for 
1.9GB.  sockets are a low-level facility, and it's common to 
pass a relatively small power of 2 (for best match with 
hardware and network realities).

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Comment By: Jeremy Hylton (jhylton)
Date: 2003-06-18 12:02

Message:
Logged In: YES 
user_id=31392

What happens when you write a C program that does the same
thing?  I expect you'll see similar problems.


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