On 2016-05-18 15:20, Daniel Holth wrote: > I would like to take another stab at adding a threadlocal "str(bytes) > raises an exception" to the Python interpreter, but I had a very hard > time understanding both how to add a threadlocal value to either the > interpreter state or the threadlocal dict that is part of that state, > and then how to access the same value from both Python and CPython code. > The structs were there but it was just hard to understand. Can someone > explain it to me?
Python has a two important states related to threads. The PyInterpreterState contains the state of an interpreter instance: sys module, loaded modules and a couple of additional settings. Usually there is just one interpreter state in a Python process. Additional interpreter states are used to implement subinterpreters. Each C thread, that wants to run Python code, must have a PyThreadState. The thread state contains a reference to a PyInterpreterState. Each PyThreadState has a PyObject *dict member. You can stick Python objects into the dict. The interpreter cleans up the dict when it reaps a thread. How performance critical is your code? Does the interpreter have to check the value of the thread local frequently? In that case you should add a new member to typedef struct _ts PyThreadState in pystate.h right before /* XXX signal handlers should also be here */. Otherwise you can simply use PyThreadState_GetDict(). It returns a Python dict object that is local to the current thread. You can simply use a fixed key like in Modules/_decimal/_decimal.c. Christian _______________________________________________ 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
