matplotlib/matplotlib — pull request #1587 by mdehoon (2012-12-11 04:57:27+00:00)
Title: Mac OS X 10.5 needs an autoreleasepool here to avoid memory leaks. Newer...

... versions of Mac OS X do not, but it doesn't hurt to have one anyway. Without the autorelease pool, on Mac OS X 10.5 show() leaks memory and the OS prints error messages.