On 3 April 2016 at 17:32, Serhiy Storchaka <storch...@gmail.com> wrote: > Originally I proposed a pair of macros for safe reference replacing to > reflects the duality of Py_DECREF/Py_XDECREF. [1], [2] The one should use > Py_DECREF and the other should use Py_XDECREF. > > But then I got a number of voices for the single name [3], and no one voice > (except mine) for the pair of names. Thus in final patches the single name > Py_SETREF that uses Py_XDECREF is used. Due to adding some overhead in > comparison with using Py_DECREF, this macros is not used in critical > performance code such as PyDict_SetItem().
I was one of those arguing for the single macro, and I think Alexander raises a good point in http://bugs.python.org/issue26200#msg262204 that I don't recall seeing in the original discussion: the "X" in the macro serves as a good shorthand for indicating that the code in question isn't closely tracking whether or not manipulated reference might be NULL, and hence may be a good candidate for additional micro-optimisations that keep better track of whether or not the pointer is NULL. > Should we rename Py_SETREF to Py_XSETREF and introduce new Py_SETREF that > uses Py_DECREF? With the single-macro design put into effect and concrete problems arising from that, I'm now more persuaded by the consistency argument than I was originally, so +1 from me for reverting to your original dual-macro proposal. Cheers, Nick. -- Nick Coghlan | ncogh...@gmail.com | Brisbane, Australia _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
