// filename:c2011-F-10-6-1-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.10.6.1 The ceil 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 ceil_a(double x)
{
double result;
int save_round = fegetround();
fesetround(FE_UPWARD);
result = rint(x); // or nearbyint instead of rint
fesetround(save_round);
return result;
}
	#define MAX 5
int main(){
	double value[]={3.14159,-2.5, 0.0, FP_INFINITE,FP_NAN},ret,ret_a;
	for(int i=0;i<MAX;i++){
		ret = ceil(value[i]);
		ret_a = ceil_a(value[i]);
   	printf("ceil( %f) = %f, ceil_a() = %f, true=%d\n", value[i], ret, ret_a,(ret==ret_a) );
	}
	return printf("F.10.6.1 The ceil functions\n");
}
// 1. warning LLVM 3.2
//c2011-F-10-6-1-ex.c:17:14: warning: pragma STDC FENV_ACCESS ON is not supported, ignoring pragma [-Wunknown-pragmas]
//#pragma STDC FENV_ACCESS ON
//             ^
//1 warning generated.
//  output LLVM 3.2 & GCC4.9 
//ceil( 3.141590) = 4.000000, ceil_a() = 4.000000, true=1
//ceil( -2.500000) = -2.000000, ceil_a() = -2.000000, true=1
//ceil( 0.000000) = 0.000000, ceil_a() = 0.000000, true=1
//ceil( 2.000000) = 2.000000, ceil_a() = 2.000000, true=1
//ceil( 1.000000) = 1.000000, ceil_a() = 1.000000, true=1
//F.10.6.1 The ceil functions