//	This example shows how to use libfpe.a 
//	from within  a C++ program. Refer to the 
//	handle_sigfpes(3C) man page for additional  
//	information. 
// 
//	CC fpe_handler4.c -o fpe_handler4 -lfpe 
//	fpe_handler4 
// 
//	UNDERFLOW occurred 
//	returned value for the UNDERFLOW is 10.000000 
// 
//	OVERFLOW occurred 
//	returned value for the OVERFLOW is 20.000000 
// 
//	DIVIDE BY ZERO occurred 
//	returned value for the DIVIDE BY ZERO is 
//		30.000000 
// 
//	INVALID occurred 
//

#include <sigfpe.h> 
#include <stdio.h> 
#include <limits.h> 
#include <math.h>
void handler_rout(int exception[5], float ret_val[2]) 

{ 
	// This module determines what fpe occurred 
	// and sets the result  of the fpe 
	// accordingly. 
	// 

	switch(exception[_EXCEPTION_TYPE]) { 
		case _UNDERFL : 
			printf("UNDERFLOW occurred\n"); 
			ret_val[0] = 10.0; 
			break; 
		case _OVERFL : 
			printf("OVERFLOW occurred\n"); 
			ret_val[0] = 20.0; 
			break; 
		case _DIVZERO : 
			printf("DIVIDE BY ZERO occurred\n"); 
			ret_val[0] = 30.0; 
			break; 
		case _INVALID : 
			// There is currently a bug in the 
			// libfpe.a library  that prevents a 
			// replacement value from being  
			// assigned to `ret_val' in the case 
			// of INVALID FPE.  For now just 
			// recognize INVALID FPE. 
			printf("INVALID occurred\n"); 
			break; 
	} 
}

main() 
{ 
	int i; 
	float res,min,max,zero,ten;
	// 
	// The elements of the sigfpe_ array are 
	// interpreted as follows:
	// sigfpe_[0] is ignored. 
	// sigfpe_[1] is the structure for _UNDERFL 
	// sigfpe_[2] is the structure for _OVERFL 
	// sigfpe_[3] is the structure for _DIVZERO 
	// sigfpe_[4] is the structure for _INVALID -
	// Each structure contains the following:
	// struct sigfpe_template 
	// 		{ 
	// 		int repls; 	The replacement value 
	// 		int count; 	The count limit 
	// 		int trace; 	The trace limit 
	// 		int abort; 	The abort limit 
	// 		int exit ; 	The exit limit 
	// }; 
	//
	//	Initialize the sigfpe_ array to cause 
	//	floating point exceptions to be handled by 
	//	the process. The replacement value for the 
	//	result  will be determined in handler_rout. 
	//
	for (i = 1; i < _N_EXCEPTION_TYPES+1 ; i++ ) { 
		sigfpe_[i].repls = _USER_DETERMINED; 
	}
	// Establish handler_rout() to be the module 
	// to handle SIGFPEs 

	handle_sigfpes (_ON, _EN_UNDERFL | \
		_EN_OVERFL | _EN_DIVZERO | _EN_INVALID,\ 
		(void (*)(unsigned int *, int \
		*))handler_rout, 0, 0);

	// Lets generate some floating point 
	// exceptions 
	min = FLT_MIN; 
	max = FLT_MAX; 
	ten = 10.0; 
	zero = 0.0;
	res = min/ten; 

	printf(" returned value for the UNDERFLOW \
		is %f\n\n",res);
	res = max*ten; 
	printf(" returned value for the OVERFLOW \
		is %f\n\n",res);
	res = ten/zero; 
	printf(" returned value for the DIVIDE BY \
		ZERO is %f\n\n",res);
	// Cause and INVALID fpe. 
	res = zero/zero; 
}