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Re: Problems with PR 21210
- From: Mark Mitchell <mark at codesourcery dot com>
- To: "Nathan (Jasper) Myers" <ncm at codesourcery dot com>
- Cc: Benjamin Kosnik <bkoz at redhat dot com>, gdr at integrable-solutions dot net, jason at redhat dot com, libstdc++ at gcc dot gnu dot org, gcc-patches at gcc dot gnu dot org, nathan at codesourcery dot com
- Date: Tue, 31 May 2005 20:09:37 -0700
- Subject: Re: Problems with PR 21210
- References: <200505292006.j4TK6ktK008048@sethra.codesourcery.com> <xyphdgkpc53.fsf@miranda.boston.redhat.com> <429B9AAF.30509@codesourcery.com> <m34qckfc3j.fsf@uniton.integrable-solutions.net> <429BBDDE.10301@codesourcery.com> <20050531170242.6a3d8f55.bkoz@redhat.com> <429CE32D.3060801@codesourcery.com> <20050601023843.GC8966@codesourcery.com>
Nathan (Jasper) Myers wrote:
On Tue, May 31, 2005 at 03:20:29PM -0700, Mark Mitchell wrote:
I'm not sure what other areas of concern arise, with respect to this PR,
which is just about the core language.
There are indeed other questions, though, like:
1. Overload resolution
void f(std::complex<double>);
void f(__complex__ double);
2. Should we have overloads of "sin" (and so forth) for "__complex__"
types?
The Intent of the Committee was that compilers would open-code complex
and val_array objects if there was anything to be gained by it.
That is, std::complex<> and __complex__ ought to one and the same
type. I hope the C committee has not given them such different
semantics that it's impossible.
(From now on, I'm going to call __complex__ by its official C99 name,
which is _Complex.)
Every libstdc++ std::complex<> presently contains a _Complex, so making
them the same type would break that. But, yes, it would be cool if they
were magically the same type.
Under this interpretation, would you have to #include <complex> before
you got to use _Complex? That's not true in C99. But, if _Complex in
C++ is going to be the same type as std::complex, then it seems like
you'd have to have the header to make everything make sense.
Or do you mean that there should be a magic rule that declares _Complex
and std::complex compatible types, even though they're spelled differently?
--
Mark Mitchell
CodeSourcery, LLC
mark@codesourcery.com
(916) 791-8304