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Date: Fri, 9 Mar 2012 12:02:54 -0500
From: Rich Felker <dalias@...ifal.cx>
To: musl@...ts.openwall.com
Subject: Re: libm

On Fri, Mar 09, 2012 at 10:56:55AM -0500, Rich Felker wrote:
> > > Then add __RETCAST((x)), __RETCAST((x)+(y)), etc. Some trick will be
> > > needed to make integer types result in a cast to double, though.
> > 
> > hm the int->double and complex/real cases are tricky
> > 
> > i thought +1.0 or +I would solve these, but that's wrong
> 
> I think +0.0f might solve it. Isn't the promoted type of any integer
> type with float double?

Nope, it results in float. glibc has a trick involving obscure
interactions of null pointer constants and the ?: operator that
generates the right type using __typeof__, which is no big deal
because this code is already only used when __typeof__ is available,
anyway.

There's a good blog article on it somewhere which I can't seem to find
at the moment...

Rich

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