[Bug c++/108342] std::complex: ignoring packed attribute because of unpacked non-POD field

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108342

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |jakub at gcc dot gnu.org

--- Comment #11 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Rui Oliveira from comment #10)
> So my options are to create like a placeholder, say 
> 
> ```c
> typedef struct __attribute__((__packed__)) // Packed isn't really necessary
> here I think?
> {
>     float re, im;
> } ph_fcomplex_t
> 
> ```
> 
> To silence the warning and get packing to work, and trust
> [complex.numbers.general] for a reinterpret_cast into std::complex<float> I
> guess.

No, if you have the packed ph_fcomplex_t not aligned at alignof (float), you
need
to copy it to a properly aligned variable before trying to reinterpret_cast it.