On Mon, 11 Jan 2010 10:09:36 +0100, Martin v. Loewis wrote: >> In Python 3.1 is there any difference in the buffering behavior of the >> initial sys.stdout and sys.stderr streams? > > No. > >> Were they different at some earlier point in Python's evolution? > > That depends on the operating system. These used to be whatever the > C library set up as stdout and stderr. Typically, they were buffered > in the same way.
On Unix, stdout will be line buffered if it is associated with a tty and fully buffered otherwise, while stderr is always unbuffered. On Windows, stdout and stderr are unbuffered if they refer to a character device, fully buffered otherwise (Windows doesn't have line buffering; setvbuf(_IOLBF) is equivalent to setvbuf(_IOFBF)). ANSI C says: As initially opened, the standard error stream is not fully buffered; the standard input and standard output streams are fully buffered if and only if the stream can be determined not to refer to an interactive device. -- http://mail.python.org/mailman/listinfo/python-list
