Marc Tompkins wrote: > On Nov 17, 2007 8:14 PM, Kent Johnson <[EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]>> wrote: > Have you tried specifying a buffer size in the open() call? > > Yes. > I compared: > - no buffer size specified > - any of a wide range of positive numbers (from 1 to 4M) > - -1 > and saw no noticeable difference - as opposed to adding the StringIO > buffering, which kicked things up by a notch of six or so. > > By the way, this is really obscurely documented.
It is documented in the official docs of the open() function, that can't really be called obscure: http://docs.python.org/lib/built-in-funcs.html#l2h-54 though I admit that this section of the docs itself is not as well-known as it should be. (I strongly recommend that all learning Pythonistas read sections 2.1 and 3 of the Library Reference.) It took me a lot of > Googling to find even one mention of it - in Programming Python by Mark > Lutz - and I was very excited... until I tested it and found that it did > nothing for me. Bummer. Then I re-read the passage: > > /Buffer size/ > > The open call also takes an optional third buffer size argument, > which lets you control stdio buffering for the file -- the way > that data is queued up before being transferred to boost > performance. If passed, means file operations are unbuffered Should read, "If 0 is passed" > I've only tested on Windows XP; is XP one of those that don't provide > sevbuf? (Actually, I think that's a typo - I think it should be > "setvbuf" - but it exists in both the 2001 and 2006 editions of the > book.) Yes, it is correctly spelled in the official docs: http://docs.python.org/lib/built-in-funcs.html#foot1196 Kent _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
