[Python-Dev] Moving forward on the object memory API (original) (raw)

Guido van Rossum guido@python.org
Mon, 01 Apr 2002 10:33:08 -0500

Guido van Rossum wrote: > No, it's for the binary API. There's a test in PyInitModule() that > checks whether a dynamically loaded extension uses the same API as the > core, and that's definitely a binary compatibility issue.

I was under the impression that the binary API changes in every minor release.

The API version number doesn't always. Maybe we're going about this wrong though: when we only add to the API, we don't change the API version number, on the theory that extensions that worked before still work. But of course extensions that use the added API functions won't work on the older systems, despite having the same API number. (However, they will get a different kind of error, from the linker.)

I think I try to change the API version number when there are incompatible changes in object lay-out which would trip you up even if the functions haven't changed. An example would be adding the hash field to the string object, which requires recompilation for every extension that uses the PyString_AS_STRING macro. (This happened many years ago of course.)

--Guido van Rossum (home page: http://www.python.org/~guido/)