<stdfloat>

[spinicist]

Godbolt example: https://godbolt.org/z/rhd7vvT79

I'm having difficult with the types in , i.e. std::float16_t and std::float32_t. std::print can print a std::float16_t, but fmt::print cannot. Neither std::print or fmt::print can print a std::complex<std::float16_t>.

What is needed to format/print a std::complex<std::float16_t>? Is this something I can add a formatter for in my own code?

Thanks.

[spinicist]

I attempted to provide a formatter for float16_t, but fmt::print doesn't find it https://godbolt.org/z/j39n8185W

Is this because float16_t lives in std?

[sunmy2019]

Is this because float16_t lives in std?

No. formatter only works for struct/class/union/enum/array.

What is needed to format/print a std::complexstd::float16_t? Is this something I can add a formatter for in my own code?

Yes. Just add a new formatter specialization.

[sunmy2019]

Fixing this requires an abi imcompatible change in fmt library. This will not available until next major release.

You can cast to f32 at now, or use a struct wrapper and implement formatter for it.

[spinicist]

What needs to change - is it type_mapper?

Casting at the call site isn't really feasible throughout my code base, sadly.

[vitaut]

What is needed to format/print a std::complexstd::float16_t? Is this something I can add a formatter for in my own code?

Normally you should only add formatters for code you control, so a supported way to do this is via a wrapper type in your namespace.

[spinicist]

I'm happy to help with a PR to fix this properly but need some pointers on where to start. ABI isn't an issue for me. While it seems I'm the first person to try formatting a float16_t I can't imagine I'll be the last.

[vitaut]

The FP implementation will soon be replaced with https://github.com/vitaut/zmij so the first step would be to add float16_t support there.