Segmentation fault creating PyArrayObject using PyArray_SimpleNew

Question

I am creating a C extension for NumPy. The function should return an array, so I decided to create a PyArrayObject with dimensions 50x10 using PyArray_SimpleNew and later fill it with some values. Here is the code:

PyArrayObject *a; npy_intp dims[2];
dims[0] = 50; dims[1] = 10;
a = (PyArrayObject *) PyArray_SimpleNew(2, dims, NPY_DOUBLE);

However, the creation of the array a in the third line produces Segmentation Fault. Any idea what could be the problem?

maybe creating numpy array in c extension segfaults helps, did you call import_array() ? — Thomas
– Thomas, Commented Apr 16, 2020 at 21:02
Oh, thank you. I just posted a solution because I did not check your comment before. Anyway, it indeed fix the problem. Now the question is why? — German Farinas
– German Farinas, Commented Apr 16, 2020 at 21:47
"void import_array(void): This function must be called in the initialization section of a module that will make use of the C-API. It imports the module where the function-pointer table is stored and points the correct variable to it." textually copied from NumPy C-API doc. — German Farinas
– German Farinas, Commented Apr 16, 2020 at 21:56
Does this answer your question? creating numpy array in c extension segfaults — TylerH
– TylerH, Commented Dec 14, 2023 at 16:33

gre_gor · Accepted Answer · 2023-12-14 16:50:02Z

4

I needed to include import_array() in my init function as shown below. I don't know what import_array() does, but fix the problem.

PyMODINIT_FUNC
PyInit_multpy(void)
{
    import_array();
    return PyModule_Create(&multpymodule);
}

PS: It would be wonderful to know why import_array() has to be called in the PyMODINIT_FUNC. If somebody knows, please explain.

edited Dec 14, 2023 at 16:50

gre_gor

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answered Apr 16, 2020 at 21:44

German Farinas

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