DLL load failed while importing bindings.

[Alcantor]

Hello,

I've got this error on a fresh python 3.14 installation. Is a DLL missing into the package? I've tried to put libusb-1.0.dll without success.

I've installed the package with "python -m pip install python-can-candle" under windows 11.

Python 3.14.4 (tags/v3.14.4:23116f9, Apr  7 2026, 14:10:54) [MSC v.1944 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import candle_api
Traceback (most recent call last):
  File "<python-input-0>", line 1, in <module>
    import candle_api
  File "C:\Users\win11user\AppData\Local\Programs\Python\Python314\Lib\site-packages\candle_api\__init__.py", line 1, in <module>
    from candle_api.bindings import (
    ...<9 lines>...
    )
ImportError: DLL load failed while importing bindings: The specified module could not be found.
>>>

[lukehugh]

Using cibuildwheel or python -m build.

You can see our workflow here: https://github.com/BIRLab/candle_api/blob/main/.github/workflows/publish-to-pypi.yml

[Alcantor]

I've installed it indirectly by using "python -m pip install python-can-candle". So I guess it should load a pre-compiled one...

[lukehugh]

I'm not sure, but the PyPI package we released does include the pyd files.

candle_api-0.0.12-cp314-cp314-win_amd64.whl

Maybe you could try reinstalling it?

[Alcantor]

I investigated further using a dependency analysis tool on the .pyd file and found that VCRUNTIME140_THREADS.dll was missing.

Installing the latest Microsoft Visual C++ 14 Redistributable package resolved the issue.

Unfortunately, the import error is not very informative and does not clearly indicate which DLL is missing.

[lukehugh]

@Alcantor Thank you for your in-depth analysis. Because we enabled the native C11 threads in our Windows build, candle_api requires vcruntime140_threads.dll to run. This has indeed caused some runtime issues, as candle_api cannot check whether vcruntime140_threads is available before loading itself. We will consider enabling the TinyCThread wrapper on Windows to reduce friction. I'll keep this issue open until we resolve it. Thanks again.