floating point control on windows

Thanks for the guidance.

Using the following code fixed my problem:

#ifdef _WIN32
BOOL APIENTRY DllMain( HANDLE hModule, 
                       DWORD  ul_reason_for_call, 
                       LPVOID lpReserved
					 )
{
	if (ul_reason_for_call == DLL_PROCESS_ATTACH)
	{
		Rwin_fpset();
	}

    return TRUE;
}
#endif

-----Original Message-----
From: Prof Brian Ripley [mailto:ripley at stats.ox.ac.uk] 
Sent: Monday, August 29, 2005 10:53 AM
To: Chris Paulse
Cc: r-devel at r-project.org
Subject: Re: [Rd] floating point control on windows

We recommend calling Rwin_fpset() which is exported by R.dll and is known
to do the trick.  As it contains

     _controlfp(_PC_64, _MCW_PC);

it may be that the args you used are incorrect (and I am not on Windows 
to check the docs, but note that is the form used in the URL you cite).

Hi,

I'm sure that this question has come up many times before.  When I load an

R

extension dll I've built with the Microsoft compiler, I get the warning:

Warning message:

DLL attempted to change FPU control word from 8001f to 9001f

So, what I did to try to fix the problem (to my knowledge, Microsoft will
not support compile time switching of floating point control until version
8.0 of their compiler - see: http://blogs.msdn.com/ericflee) was to place
the following statement inside R_init_mylib:

_controlfp(_MCW_PC, _PC_64); // use extended precision for operations in

x87

FPU

This didn't fix my problem.  I ended up sprinkling these liberally
throughout my code, but that didn't help.  One thing I do like about the
Microsoft compiler is the debugging facility.  But, I'll definitely switch
to gcc if this is necessary to get rid of the problem.

Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595