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Date: Wed, 29 Jan 2014 13:59:28 -0800
From: Steve Kargl <sgk@troutmask.apl.washington.edu>
To: Dmitry Marakasov <amdmi3@amdmi3.ru>
Subject: Re: libm lacks C99 functions -> no c++11 cmath in libstdc++
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On Wed, Jan 29, 2014 at 10:47:35PM +0400, Dmitry Marakasov wrote:
> * Steve Kargl (sgk@troutmask.apl.washington.edu) wrote:
> 
> > > - bad enough by itself, it affects libstdc++ from ports' gcc in such a
> > >   way that it disables C++11 math completely (along with a lot more
> > >   other more widely used math functions)
> > >
> > >
> > > - we may probably implement these by calling less-precise
> > >   erf erfc lgamma tgamma as we do with other functions as we alredy
> > >   do with some others
> > 
> > This, unfortuantely, has already been done, although it may only 
> > be available in FreeBSD-current.  See src/lib/msun/src/imprecise.c.
> 
> I know, it's available on 10.0 as well. However that's not the case for
> 9.x, for which it's impossible to build c++11 math using software (even
> if it doesn't use unimplemented functions), neither with system gcc
> nor with gcc from ports.
> 

It's not impossible.  Add whatever C++-fu you need
that is equivalent to

#include <math.h>
#ifndef fool
#define fool(x)	foo((double)(x))
#endif

-- 
Steve