[Python-Dev] xreadlines : readlines :: xrange : range
Guido van Rossum
Thu, 11 Jan 2001 10:27:05 -0500
> Think like an implementer here <0.5 wink>: they've lost track of how many
> characters are in the buffer despite a locking scheme whose purpose is to
> prevent that. If it were my implementation, that would be a top-priority
> bug no matter how silly the first program I saw that triggered it.
The locking prevents concurrent threads accessing the stream.
But mixing reads and writes (without intervening fseek etc.) is
illegal use of the stream, and the C standard allows them to be lax
here, even if the program was single-threaded.
In other words: the locking is so good that it serializes the sequence
of reads and writes; but if the sequence of reads and writes is
illegal, they don't guarantee anything.
--Guido van Rossum (home page: http://www.python.org/~guido/)