Re: [PATCH 0/2] MR7748: ucrtbase: Add cexp() implementation.

[Piotr Caban (＠piotr)]

Piotr Caban (@piotr) commented about libs/musl/src/internal/complex_impl.h:
> +#ifndef _COMPLEX_IMPL_H
> +#define _COMPLEX_IMPL_H
> -
>
> +#include <complex.h>
> +#include "libm.h"
> -
>
> +#undef __CMPLX
> +#undef CMPLX
> +#undef CMPLXF
> +#undef CMPLXL
> -
>
> +#define __CMPLX(x, y, t) \
> - ((union { t __z; t __xy[2]; }){.__xy = {(x),(y)}}.__z)

While this code does what you want it looks non portable / over complicated. At least __xy type should be changed to something like:
```c
#define __CMPLX(x, y, t, t2) \
        ((union { t __z; t2 __xy[2]; }){.__xy = {(x),(y)}}.__z)

#define CMPLX(x, y) __CMPLX(x, y, _Dcomplex, double)
```
It could be simplified even further to:
```c
#define __CMPLX(x, y, t) ((t){(x), (y)})
```

I'm afraid that none of this code is portable (at least it will not compile with MSVC).