Check if PyObject is None

Question

I would just like to check if a PyObject that I have is None. I naively expected that any None Pyobject * returned from a function would be a NULL pointer, but that doesn't seem to be the case.

So: how do I check if a PyObject * of mine points to a None object?

I know that there are macros like PyInt_Check(PyObject *) around, but I couldn't find anything like PyNone_Check. I thought I could just check the equality between my PyObject and Py_None, but turns out I don't even know how to make equality comparisons with this library.

user2555451 · Accepted Answer · 2015-04-19 16:57:28Z

32

You can just compare directly with Py_None using ==:

if (obj == Py_None)

From the docs:

Note that the PyTypeObject for None is not directly exposed in the Python/C API. Since None is a singleton, testing for object identity (using == in C) is sufficient. There is no PyNone_Check() function for the same reason.

answered Apr 19, 2015 at 16:57

user2555451

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qbizzle68 · Accepted Answer · 2024-11-09 04:48:52Z

0

For anyone that may come across this, as of 3.10 there is now the Py_IsNone() function which the docs state:

Test if an object is the None singleton, the same as x is None in Python.

answered Nov 9, 2024 at 4:48

qbizzle68

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