On Sat, 12 Feb 2022, Uecker, Martin via Liaison wrote:

> > Whether C++ wants to support "_Complex T" as an
> > alias for std::complex<T> should be a global feature, to be
> > decided on its own merits.
>
> Complex exists for two decades in C and the
> compatibility story is still poor.

In particular, the function calling ABI for _Complex (in C) may not always
be the same as that for std::complex, which would be a problem for
treating _Complex as an alias.

(C++ also has some operations on complex numbers that aren't in C, but
having additional library functions like that isn't a compatibility
concern as long as C doesn't add such functions in an incompatible form.)

-- 
Joseph S. Myers
joseph_at_[hidden]