// filename:c2011-F-10-3-12-ex.c
// original examples and/or notes:
// 		(c) ISO/IEC JTC1 SC22 WG14 N1570, April 12, 2011
// http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf
// 			C2011 F.10.3.12 The modf functions
// compile and output mechanism:
// 		(c) Ogawa Kiyoshi, kaizen@gifu-u.ac.jp, January.04, 2014
// compile errors and/or wornings:
// 1	(c) Apple LLVM version 4.2 (clang-425.0.27) (based on LLVM 3.2svn)
// 			Target: x86_64-apple-darwin11.4.2 //Thread model: posix
// 		(c) LLVM 2003-2009 University of Illinois at Urbana-Champaign.
// 2    gcc-4.9 (GCC) 4.9.0 20131229 (experimental)
//      Copyright (C) 2013 Free Software Foundation, Inc.
#include <stdio.h>
#include <math.h>
#include <fenv.h>
#pragma STDC FENV_ACCESS ON
double modf_a(double value, double *iptr)
{
	int save_round = fegetround();
	printf("save_round =%d ",save_round);
fesetround(FE_TOWARDZERO);
	*iptr = nearbyint(value);
	printf("nearbyint(value)=%f ",*iptr);
	fesetround(save_round);
	printf("isinf=%d =%f ",isinf(value),value);
	printf("copysign=%f =%f \n",copysign(isinf(value) ? 0.0 :value - (*iptr), value),value - (*iptr));
return copysign(
isinf(value) ? 0.0 :
value - (*iptr), value);
}
	#define MAX 5
int main(){
	double value[]={3.14159,-2.5, 0.0, FP_INFINITE,FP_NAN},ret,ret_a,iptr,iptr_a;
	for(int i=0;i<MAX;i++){
		ret = modf(value[i],&iptr);
		ret_a = modf_a(value[i], &iptr_a );
   	printf("modf( %f, exp ) = %f, exp = %f, modf_a(,) = %f exp_a=%f , true=%d\n", value[i], ret, iptr,ret_a,iptr_a,((ret==ret_a) & (iptr==iptr_a)) );
	}
	return printf("F.10.3.12 The modf functions\n");
}
//  output will be 
//save_round =0 nearbyint(value)=256 isinf=0 =3.141590 copysign=768 =0.141590 
//modf( 3.141590, exp ) = 0.141590, exp = 1, modf_a(,) = 3.000000 exp_a=28862176 , true=0
//save_round =0 nearbyint(value)=1536 isinf=0 =-2.500000 copysign=2048 =-0.500000 
//modf( -2.500000, exp ) = -0.500000, exp = 1, modf_a(,) = -2.000000 exp_a=0 , true=0
//save_round =0 nearbyint(value)=2816 isinf=0 =0.000000 copysign=3328 =0.000000 
//modf( 0.000000, exp ) = 0.000000, exp = 1, modf_a(,) = 0.000000 exp_a=0 , true=0
//save_round =0 nearbyint(value)=4096 isinf=0 =2.000000 copysign=4608 =0.000000 
//modf( 2.000000, exp ) = 0.000000, exp = 1, modf_a(,) = 2.000000 exp_a=0 , true=0
//save_round =0 nearbyint(value)=5376 isinf=0 =1.000000 copysign=5888 =0.000000 
//modf( 1.000000, exp ) = 0.000000, exp = 1, modf_a(,) = 1.000000 exp_a=0 , true=0
//F.10.3.12 The modf functions