To followup on this: Terry: Yes, I did in fact miss the 'buffer' parameter to open. Setting the buffer parameter to 0 did in fact fix the test code that I gave above, but oddly, did not fix my actual production code; it continues to get the data as first read, rather than what is currently on the disk. I'm still investigating why.
Carl: I tried the above test code, without 'buffer=0' in the open, but with a flush added before reads in the appropriate places. The flush made no difference; readline continued to return the old data rather than what was actually on the disk. So, flush isn't the answer. I suppose that means that, when the document states it flushes the buffer, it's referring to the output buffer, not the input buffer. -- http://mail.python.org/mailman/listinfo/python-list