Description

Yosh31207

opened on Sep 26, 2026

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PyBuffer.GetPointer throws System.ExecutionEngineException when called with an N-dimensional array obtained with PyBUF.ND flag.

dynamic np = Py.Import("numpy");

// create 3D NumPy array
int[] shape = [10, 10, 10];
PyObject ndArray = np.zeros(shape);

PyBuffer buf = ndArray.GetBuffer(PyBUF.ND);

// this throws System.ExecutionEngineException
nint ptr = buf.GetPointer([0, 0, 0]);

I suspect that this may be caused by a mismatch of a type. The following code seems to pass a CLR array to native function pointer.

// src/runtime/Runtime.Delegates.cs

PyBuffer_GetPointer = (delegate* unmanaged[Cdecl]<ref Py_buffer, nint[], IntPtr>)GetFunctionByName(nameof(PyBuffer_GetPointer), GetUnmanagedDll(_PythonDll));

The second argument should be nint* obtained by fixed statement, isn't it?

My environment:

• OS: Windows 11
• Python: 3.14
• Python.NET: 3.1.0
• .NET 10
• Visual Studio 2026

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1. filmor

   added

   bug

   on Sep 28, 2026
2. filmor commented on Sep 28, 2026

   

   filmor

   on Sep 28, 2026

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   I can confirm that I also see crashes in this function, but the proposed fix (fixed and nint*) does not seem to be enough. Will check further.

   Reacted by Yosh31207
3. filmor commented on Sep 28, 2026

   

   filmor

   on Sep 28, 2026

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   I can't find any useful docs on this, but the issue is PyBUF.ND:

   https://github.com/python/cpython/blob/9e9c3c49b4a41eebb982891c3ccdc17ae5ab9963/Objects/abstract.c#L544-L557

   PyObject_GetPointer accesses view->strides, so you must use at least PyBUF.STRIDES to access it. I will introduce an exception for this on PyBuffer.GetPointer.
4. filmor

   closed this as completedin #2745on Sep 29, 2026

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