windows-bindgen should generate no_std bindings by default

[mwcampbell]

Since the windows crate recently gained support for using no_std while still supporting alloc, it would be useful to have a complete example of an executable or DLL built this way. I read in #3047 that some low-level components, including in Windows itself, use the crate this way. I understand if this is an impractical request because all the real examples are too tightly coupled to Windows's build system or other proprietary bits.

[kennykerr]

While we can probably add/update a sample, there's not really much to illustrate here beyond adding #![no_std] to your lib.rs or main.rs and taking it for a spin. The compiler should quickly point out what you might be missing.

[kennykerr]

Actually, I attempted to port a sample to use no_std and ran into a few minor issues so I'll use this issue to track those and then make sure we have test coverage and a working sample.

[kennykerr]

Note to self: sample_direct2d is a good test case for this.

[mwcampbell]

What I had in mind for a complete no_std sample was things like setting up a panic handler, allocator (if you've actually figured out a way to use no_std with alloc in user space), and any other bits that are required for non-trivial no_std projects on Windows.

[kennykerr]

If you mean the alloc crate then you can find various examples by searching this repo. It is used for allocation support under no_std.

If you mean a custom allocator then you may want to look at https://github.com/microsoft/windows-drivers-rs for examples.

[mwcampbell]

@kennykerr Are you still planning to make the sample_direct2d project no_std as a test case and demo?

[kennykerr]

Yes, this issue was mostly resolved by #3359 but I'll open again to address some remaining issues and update the sample.

[kennykerr]

Thanks for checking! 🙂

[kennykerr]

@mwcampbell I decided against updating the sample as it butched the sample undesirably, but I fixed the underlying code gen and added tests to ensure that everything should build with no_std if so desired.

Please take #3366 for a spin and let me know if you run into any problems.