[Python-Dev] Py_END_ALLOW_THREADS and GetLastError() (original) (raw)

"Martin v. Löwis" martin at v.loewis.de
Sat Jan 10 15:11:16 CET 2009

Well, that's what you get for using globals

Please do take a look at the issue at hand before pointing fingers. First, GetLastError() isn't a really a global (and neither is errno); they are both thread-local. Next, there is really no choice to use or not use errno - if you want to find out what the error is that has occurred, you have to look at errno. Finally, in the case of Py_END_ALLOW_THREADS, errno/GetLastError is typically read right after the system call. However, you can't raise the Python exception before Py_END_ALLOW_THREADS (which you seem to suggest as a solution), since we must not call Python APIs without holding the GIL.

Generally, I would discourage non-local errno use. My motivation is that MS Windows CE simply doesn't have errno and MS Windows in general often uses different ways to signal errors, so not using it would restrict the conditionally compiled code further.

That sounds like an unrelated issue to the one at hand.

Regards, Martin

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