On Mon, Dec 19, 2016 at 1:11 PM, Nick Coghlan <ncogh...@gmail.com> wrote: > On 17 December 2016 at 03:51, Antoine Pitrou <solip...@pitrou.net> wrote: >> >> On Fri, 16 Dec 2016 13:07:46 +0100 >> Erik Bray <erik.m.b...@gmail.com> wrote: >> > Greetings all, >> > >> > I wanted to bring attention to an issue that's been languishing on the >> > bug tracker since last year, which I think would best be addressed by >> > changes to CPython's C-API. The original issue is at >> > http://bugs.python.org/issue25658, but I have made an effort below in >> > a sort of proto-PEP to summarize the problem and the proposed >> > solution. >> > >> > I haven't written this up in the proper PEP format because I want to >> > see if the idea has some broader support first, and it's also not >> > clear to me whether C-API changes (especially to undocumented APIs) >> > even require their own PEP. >> >> This is a nice detailed write-up and I'm in favour of the proposal. > > > Likewise - we know the status quo isn't right, and the proposed change > addresses that. In reviewing the patch on the tracker, the one downside I've > found is that due to "pthread_key_t" being an opaque type with no defined > sentinel, the consuming code in _tracemalloc.c and pystate.c needed to add > separate boolean flag variables to track whether or not the key had been > created. (The pthread examples at > http://pubs.opengroup.org/onlinepubs/009695399/functions/pthread_key_create.html > use pthread_once for a similar effect) > > I don't see any obvious way around that either, as even using a small struct > for native pthread TLS keys would still face the problem of how to > initialise the pthread_key_t field.
Hmm...fair point that it's not pretty. One way around it, albeit requiring more work/complexity, would be to extend this proposal to add a new function analogous to pthread_once--say--PyThread_call_once, and an associated Py_once_flag_t _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
