STINNER Victor added the comment: > The question is why does it behave this way in the first place? > Maybe for sub-interpreters?
The code is old. I don't think that it's related to subinterpreter. PyThread_set_key_value() is used in _PyGILState_Init() and PyGILState_Ensure(), but its behaviour when the key already exists doesn't matter because these functions only call PyThread_set_key_value() once pr thread. It was probably simpler to implement PyThread_set_key_value() like it is nowadays. When the native TLS support was added, the new functions just mimic the old behaviour. Code history. find_key() function has been added at the same time than the PyThreadState structure. set_key_value() was already doing nothing when the key already exists. It looks like set_key_value() was not used. --- changeset: 5405:b7871ca930ad branch: legacy-trunk user: Guido van Rossum <gu...@python.org> date: Mon May 05 20:56:21 1997 +0000 files: Include/Python.h Include/frameobject.h Include/pystate.h Include/pythread.h Include/thread.h Modules/threadmodule.c Objects/frameobject description: Massive changes for separate thread state management. All per-thread globals are moved into a struct which is manipulated separately. --- TLS only started to be used in CPython since the following major change: --- changeset: 28694:a4154dd5939a branch: legacy-trunk user: Mark Hammond <mhamm...@skippinet.com.au> date: Sat Apr 19 15:41:53 2003 +0000 files: Include/pystate.h Include/pythread.h Lib/test/test_capi.py Modules/_testcapimodule.c Modules/posixmodule.c Python/ceval.c Python/pystat description: New PyGILState_ API - implements pep 311, from patch 684256. --- Native TLS support is very recent (compared to the first commit): --- changeset: 64844:8e428b8e7d81 user: Kristján Valur Jónsson <krist...@ccpgames.com> date: Mon Sep 20 02:11:49 2010 +0000 files: Python/pystate.c Python/thread_nt.h Python/thread_pthread.h description: issue 9786 Native TLS support for pthreads PyThread_create_key now has a failure mode that the applicatino can detect. --- ---------- nosy: +kristjan.jonsson _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue19787> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
