thanks a lot for the detailed info steve, very clearly stated!

> Yeah, geos_c.dll really should have exported its own free() function. find_library('c') is probably the wrong approach here - if geos_c.dll is being rebuilt with different CRTs at all then the free() function should be added to it, and if it's truly legacy and is no longer being rebuilt then the version of the CRT it uses should be loaded explicitly. It isn't automatically getting the same version as whatever version of Python is running, that's for sure.

well, shapely's installation instructions from windows are to use chris gohlke's prebuilt binaries from here: http://www.lfd.uci.edu/~gohlke/pythonlibs/

i assume he's coordinating the crt versions?  apparently a lot of people use these.

i'm not clear on why gohlke's stuff is necessary, and why pypi/pip/distutils is not adequate -- shapely is the only library i've run into that needed gohlke's binaries.  of course, i didn't try to install numpy/scipy manually, the internet said that this is hard on windows, and to just use something like winpython/pythonxy.  are these problems all related to this crt issue?