Windows: Dependency on msvcp140.dll intentional?

[madig]

I wasted an hour yesterday trying to track down why pyclipper (installed from PyPI) wouldn't import on a freshly installed Windows 10 PC with Python 3. Turns out the above mentioned DLL was not found (which the ImportError didn't tell me...). I was wondering if the dependency is strictly necessary?

[anthrotype]

any libraries or executables compiled with Visual Studio 2015 need the corresponding MSVC runtime DLLs installed
https://www.microsoft.com/en-us/download/details.aspx?id=48145

but python3 itself should come with that already, no?

[anthrotype]

does it change anything if you try from a virtualenv or python3 venv as opposed to from the global py -3 in the %PATH%?

[madig]

Okay, good to know.

No, that didn't change anything. In fact, there was no msvcp140.dll anywhere in C:\ except if e.g. VS Code bundled it for private use.

[anthrotype]

This may be relevant:
cztomczak/cefpython#359

Apparently Cpython only ships with the C runtime library, not the C++ one, so extension modules that use C++ need the extra step of installing the redistributable dlls from MS.

I’m not sure if it’s appropriate/worth embedding them in the wheels.

[anthrotype]

I think we just need to make this clear in the README.md with respective download links to the Microsoft website, one for each python version/MSVC/C++ redistributable DLLs that we support.