Erik Bray writes:
Abstract ========
The proposal is to add a new Thread Local Storage (TLS) API to CPython which would supersede use of the existing TLS API within the CPython interpreter, while deprecating the existing API.
Thank you for the analysis.
Further, the old PyThread_*_key* functions will be marked as deprecated. Additionally, the pthread implementations of the old PyThread_*_key* functions will either fail or be no-ops on platforms where sizeof(pythead_t) != sizeof(int).
Typo "pythead_t" in last line. I don't understand this. I assume that there are no such platforms supported at present. I would think that when such a platform becomes supported, code supporting "key" functions becomes unsupportable without #ifdefs on that platform, at least directly. So you should either (1) raise UnimplementedError, or (2) provide the API as a wrapper over the new API by making the integer keys indexes into a table of TSS'es, or some such device. I don't understand how (3) "make it a no-op" can be implemented for PyThread_create_key -- return 0 or -1? That would only work if there's a failure return status like 0 or -1, and it seems really dangerous to me since in general a lot of code doesn't check status even though it should. Even for code checking the status, the error message will be suboptimal ("creation failed" vs. "unimplemented"). I gather from references to casting pthread_key_t to unsigned int and back that there's probably code that does this in ways making (2) too dangerous to support. If true, perhaps that should be mentioned here.