uchar.h is missing on macOS

[mbrobbel]

We're using cbindgen to generate both C and C++ headers in our project. However, the generated C header fails to build on macOS with the 0.10.1 release (QE-Lab/dqcsim#313) because uchar.h is missing on macOS.

target/include/dqcsim.h:5:10: fatal error: 'uchar.h' file not found
#include <uchar.h>
         ^~~~~~~~~

[emilio]

What header defines char32_t? Is it built-in?

[emilio]

(Sorry, I don't have a mac so I cannot test that myself)

[emilio]

cc @adrianwong. Maybe we should just switch to uint32_t for now?

[mbrobbel]

What header defines char32_t? Is it built-in?

I think there is no header available, and it's not built-in unfortunately. Something like this should work I guess:

#ifdef __APPLE__
#include <stdint.h>
typedef uint16_t char16_t;
typedef uint32_t char32_t;
#else
#include <uchar.h>
#endif

[laser]

This issue also impacted our Darwin builds once we updated cbindgen from 0.10.0 to 0.10.1.

[emilio]

Ok, I put up #424 for this. I decided to use uint32_t because I also think it's needed for correctness, see the comment in the code there.

[adrianwong]

@emilio Yeah, uint32_t seems like it'll be the most appropriate type to use. The build for #424 has some test failures, which I'm happy to try fixing as this is a bug I introduced.

[emilio]

The tests in that PR seem unrelated to the change, I think it's a rust nightly change / regression (they're the cargo-expand tests, which require nightly)

[emilio]

Ah no, I just forgot to run the tests locally as I had a stable compiler. Should be green now :)

[emilio]

(But thanks a lot for the offer @adrianwong!)

[adrianwong]

Thanks for fixing this @emilio! And apologies all for not testing the <uchar.h> changes on macOS.

[emilio]

No worries, I can't test it on mac myself either, and the CI situation there is not amazing (though may be better now? We should investigate adding Mac to our CI if possible).

Thanks for being responsive (and to the reporters for the fast issue-filing :)).

[emilio]

Landed that and published v0.11.0, as it is technically a breaking change for C++ bindings unfortunately.