[Python-Dev] Add sendfile() to core?

max ulidtko ulidtko at gmail.com
Sat Jan 8 08:55:19 CET 2011

On Wed, 20 Mar 2002 14:53:58 -0500, Andrew Kuchling wrote:
| sendfile() is used when writing really high-performance Web servers,
| in order to save an unnecessary memory-to-memory copy.  Question:
| should I make up a patch to add a sendfile() wrapper to Python?

So, was this proposal rejected? If so, for what reasons?

Wrapper of such a useful call would be of great convenience, especially
considering its availability on Win32 (see Thomas Heller's notice, [1]).

Anyway, when one needs to send (arbitrarily large) files to a socket and
back, ugly and slow workarounds are born, like this one:

def copy_file(file1, file2, length, blocksize=40960):
    """ Transfer exactly length bytes from one file-like object to
another """
    sofar = 0
    while sofar < length:
        amount = blocksize if sofar + blocksize <= length \
                           else length - sofar
        sofar += amount

Using hypothetical os.sendfile() would be so much better!

The only difficulty I can see is the choice of name for the wrapper.
IMO, using "sendfile" from Linux and FreeBSD is pretty much okay; but
objections may arise.

[1] http://mail.python.org/pipermail/python-dev/2002-March/021543.html

max ulidtko

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