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Date: Tue, 25 Nov 2014 21:08:12 +0100
From: Jens Gustedt <jens.gustedt@...ia.fr>
To: musl@...ts.openwall.com
Subject: Re: [PATCH 1/4] the CMPLX macros must be usable in
initializations of static variables
Am Dienstag, den 25.11.2014, 16:25 +0100 schrieb Szabolcs Nagy:
> * Jens Gustedt <Jens.Gustedt@...ia.fr> [2014-11-25 15:49:39 +0100]:
> > +#define __CMPLX(x, y, t) ((t)(x) + _Complex_I*(t)(y))
> >
>
> this is only correct if the compiler supports annex g kind of
> imaginary type, otherwise it is incorrect for infinites
even then it would only work by using _Imaginary_I, I think
> _Complex_I*INFINITY == (0 + i)*(inf + i*0) == nan + i*inf
>
> so imaginary inf will turn into nan real part
right
(but I think it is more import to get initialization of normal complex
constants going, than the border cases with INFINITY and NAN)
to support this it seems that gcc provides __builtin_complex, so we
could implement this subject to some case analysis according to
__builtin_const etc. But since the doc for __builtin_complex
explicitly mentions C11, this probably doesn't exist for older
versions of gcc.
I'll think of it and prepare a new version of this patch
Thanks
Jens
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