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!)