Compiler warnings?

[davidbernstein]

Hi, When I include json.hpp I get many compiler warnings like

//usr/local/include/nlohmann/json.hpp(3006): warning: type qualifier is meaningless on cast type

Is there a way to suppress these? I'm on OS X with Xcode 7.2 (stuck on that version for other reasons).

Thanks,
Dave

[davidbernstein]

warnings.txt

Attached is the full set of warnings I get. Clang sadly does not tell you the compiler flags to set to ignore the warnings in some cases.

[nlohmann]

Thanks for reporting. I had a look at the warnings:

• "warning: template parameter "T" is not used in declaring the parameter types of function template" in json.hpp(1335) and json.hpp(1430): The template parameter T is in fact not used inside the function, but only to remove the function if number_integer_t/number_unsigned_t is the same as int. I am not sure how to silence this warning.
• "unused type alias 'pointee_t'": pointee_t is used in a static_assert - I have no idea why the compiler warns about this.
• "warning: unused type alias 'PointerType'": in fact, PointerType is used in the next line auto ptr = obj.template get_ptr<PointerType>();

These warnings look odd...

[davidbernstein]

Yes I noticed that 2 and 3 were warnings about unused things that are actually used. I'm assuming this is probably some clang flakiness. One of these can be ignored with the flag -Wno-unused-local-typedef. If I can find flags for the other two I'll post them here.

[gregmarr]

FYI XCode 7.2 uses Clang 7.0.2.

[davidbernstein]

Yes, that could be the problem. I'm stuck on 7.2 since this is for a CUDA project and the nvidia toolkit is not compatible with the latest Xcode.

[nlohmann]

This really seems to be a quirk of the Clang version: Apple LLVM version 8.0.0 (clang-800.0.42.1) compiles without warning when called with -Wunused-local-typedef.

[davidbernstein]

Ok then it's just me! Thanks for checking that out. We can close the issue. Other than the warnings the package is working great, it's exactly what I needed.