Troubleshooting Guide: Resolving Module Compilation Issues with Numpy API Version 0xb and 0xa

This guide will help you resolve module compilation issues related to Numpy API versions 0xb and 0xa. Numpy is a popular library for numerical computing in Python, and sometimes you may encounter issues when compiling C or C++ extensions that use its API. We'll walk you through the steps needed to troubleshoot these issues and provide solutions to common problems.

Table of Contents


Numpy's API is divided into two versions: 0xa (legacy version) and 0xb (current version). Some C or C++ extensions may not be compatible with one or both versions, causing compilation errors. These errors could result from changes in the API, deprecated functions, or incorrect usage of the API.

Source: Numpy C-API

Step-by-step Troubleshooting

Step 1: Check the Numpy version

First, you need to determine the Numpy version you're using. You can check this by running the following command in your Python environment:

import numpy as np

Step 2: Verify the API version

Check the API version used in your C or C++ extension. The API version is defined in the numpy/arrayobject.h header file.

For API version 0xb:

#define NPY_API_VERSION 0x0000000b

For API version 0xa:

#define NPY_API_VERSION 0x0000000a

Step 3: Update your code for compatibility

If your C or C++ extension is using the legacy API version 0xa, consider updating your code to use the current API version 0xb. You can find the latest documentation on the Numpy C-API page.

Step 4: Use the correct version in the C or C++ extension

Ensure that your code is using the correct API version by including the following line before including the Numpy header file:

For API version 0xb:


For API version 0xa:


Step 5: Rebuild and test

Rebuild your C or C++ extension and test it with your Numpy installation. If you still encounter issues, check the error messages and refer to the Numpy C-API documentation for guidance.


1. What are the differences between Numpy API versions 0xb and 0xa?

API version 0xb is the current version of the Numpy C-API, while 0xa is the legacy version. The main differences include updates to function signatures, data structures, and macros. You can find more information in the Numpy C-API documentation.

2. How do I ensure compatibility with both Numpy API versions?

To maintain compatibility with both API versions, you can use conditional compilation in your C or C++ extension. Use #ifdef statements to include code specific to each API version, based on the value of NPY_API_VERSION.

3. Can I use the Numpy C-API with other languages like Fortran?

Yes, you can use the Numpy C-API with other languages, including Fortran. You will need to use the appropriate language bindings and include the Numpy header files in your code.

4. What if I still encounter issues after updating my code?

If you still encounter issues after following the troubleshooting steps, consider posting a question on Stack Overflow or the Numpy mailing list with a detailed description of your problem and any error messages.

5. Can I use Numpy with GPU programming languages like CUDA?

Yes, you can use Numpy with GPU programming languages like CUDA. There are libraries like CuPy that provide a Numpy-compatible interface for GPU arrays and functions.

Great! You’ve successfully signed up.

Welcome back! You've successfully signed in.

You've successfully subscribed to

Success! Check your email for magic link to sign-in.

Success! Your billing info has been updated.

Your billing was not updated.