using bool from stdbool.h makes FFI author life difficult

[jangko]

why is it difficult:

• there is nowhere in documentation of C guarantee the size of bool. is it a byte or is it an int?
• there is no guarantee a bool in one language will have the same size with bool from C language.
• not all language FFI mechanism have access to C implementation specific feature.

please reconsider using a fixed-size replacement for bool.

EDIT: size_t have different size on 32 bit vs 64 bit platform. but it is well defined and well documented. In other hand a bool in stdbool.h does not have size definition.

[chfast]

Do you have any particular FFI project in mind?

[chfast]

Anyway, as far as the standard is concerned, even int type may have different size than 4. Similarly for enums.
But in practice the sizeof(_Bool) is 1: https://godbolt.org/z/marD9R

The problematic type is usually long which can be 4 or 8, depending on the compiler.

[jangko]

Do you have any particular FFI project in mind?

we are working to implement EVMC interface for nimbus

Anyway, as far as the standard is concerned, even int type may have different size than 4. Similarly for enums.

this is documented and well known behaviour since C89

But in practice the sizeof(_Bool) is 1: https://godbolt.org/z/marD9R

we are lucky then

I think such agreement between C compilers will pose little risk in the future.
thanks for your help. closing this issue.

[axic]

we are working to implement EVMC interface for nimbus

Please also check out #157.