[Python-Dev] Python initialization and embedded Python (original) (raw)

Antoine Pitrou solipsis at pitrou.net
Thu Nov 23 05:16:25 EST 2017

On Thu, 23 Nov 2017 10:37:59 +0100 "M.-A. Lemburg" <mal at egenix.com> wrote:

On 18.11.2017 01:01, Victor Stinner wrote: > Hi, > > The CPython internals evolved during Python 3.7 cycle. I would like to > know if we broke the C API or not. > > Nick Coghlan and Eric Snow are working on cleaning up the Python > initialization with the "on going" PEP 432: > https://www.python.org/dev/peps/pep-0432/ > > Many global variables used by the "Python runtime" were move to a new > single "PyRuntime" variable (big structure made of sub-structures). > See Include/internal/pystate.h. > > A side effect of moving variables from random files into header files > is that it's not more possible to fully initialize PyRuntime at > "compilation time". For example, previously, it was possible to refer > to local C function (functions declared with "static", so only visible > in the current file). Now a new "initialization function" is required > to must be called. > > In short, it means that using the "Python runtime" before it's > initialized by PyRuntimeInitialize() is now likely to crash. For > example, calling PyMemRawMalloc(), before calling > PyRuntimeInitialize(), now calls the function NULL: dereference a > NULL pointer, and so immediately crash with a segmentation fault.

To prevent a complete crash, would it be possible to initialize the struct entries to a generic function (or set of such functions with the right signatures), which then issue a message to stderr hinting to the missing call to PyRuntimeInitialize() before terminating ?

+1. This sounds like a good idea.

Regards

Antoine.

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