Windows support?

[kazimuth]

I'd like to use this tool for a project, but the project requires Windows support. I'm curious how far out Windows support is, and what work needs to be done to support Windows.

[anthrotype]

I tried to compile the provided example using Windows with python 3.6 and latest rust (msvc toolchain).

The only problems I found so far are:

1. the spec.find_dylib fails to find the compiled DLL because it always prefixes it with "lib" (whereas on windows DLL built with msvc the "lib" prefix is usually omitted) and the library extension is either ".dylib" (mac) or ".so", whereas on windows is ".dll" of course

2. the rtld_flags in the example's setup.py contains RTLD_NODELETE, which doesn't work on windows (commenting it out, works)

3. linking the fake extension module fails with "unresolved external symbol PyInit__native__lib"; so for Windows the hack of building the "empty.c" extension module doesn't work; it needs to actually export something.

Other than that, everything seems to work. It should be relatively simple to fix theses.
I can send some PR when I find some time, if you like.

[filmor]

I concluded exactly the same: #7

[mitsuhiko]

I merged #7 now but I wonder what the best solution for the nodelete is for rust users.

[filmor]

What do you need it for? As far as I see it, the dlopened lib is kept alive for as long as the module is kept alive.

[mitsuhiko]

@filmor maybe it's indeed not necessary on windows. On mac we get crashes in rust libraries on interpreter shutdown because rust registers TLS dtors which are not executed on lib unload.

[filmor]

If you can give me a test case I can check.

[anthrotype]

maybe it's indeed not necessary on windows

according to the cffi docs, the flags argument is ignored on Windows

For the optional flags argument, see man dlopen (ignored on Windows).

https://cffi.readthedocs.io/en/latest/cdef.html#ffi-dlopen-loading-libraries-in-abi-mode

Perhaps you could leave rtld_flags empty when sys.platform == "win32"?

[anthrotype]

oh, that's what #7 already does, sorry for the noise.

[theotherjimmy]

It looks like master supports Windows. Could we have '0.1.2' with windows support please?

[theotherjimmy]

@mitsuhiko Thanks for releasing 0.1.2! We now have windows support. I'll submit a PR to update the README shortly.

EDIT: Done. See #11

[theotherjimmy]

I take it back: Windows Wheels don't contain the .dll file.

EDIT: This is true, but not a problem. There is a .pyd file that apparently contains the .dll!?

[filmor]

The pyd is the DLL.

[theotherjimmy]

@filmor Yeah, that became clear after a bit of testing!

[mitsuhiko]

Closing this as this should work now.