isinf.c

来自「关系型数据库 Postgresql 6.5.2」· C语言 代码 · 共 68 行

/* $Id: isinf.c,v 1.6 1998/09/01 03:24:29 momjian Exp $ */

#include <math.h>
#include "config.h"

#if HAVE_FPCLASS
#if HAVE_IEEEFP_H
#include <ieeefp.h>
#endif
int
isinf(double d)
{
	fpclass_t	type = fpclass(d);

	switch (type)
	{
		case FP_NINF:
		case FP_PINF:
			return 1;
		default:
			break;
	}
	return 0;
}

#else

#if defined(HAVE_FP_CLASS) || defined(HAVE_FP_CLASS_D)
#if HAVE_FP_CLASS_H
#include <fp_class.h>
#endif
int
isinf(x)
double		x;
{
#if HAVE_FP_CLASS
	int			fpclass = fp_class(x);

#else
	int			fpclass = fp_class_d(x);

#endif

	if (fpclass == FP_POS_INF)
		return 1;
	if (fpclass == FP_NEG_INF)
		return -1;
	return 0;
}

#endif
#endif

#if defined(HAVE_CLASS)
int
isinf(double x)
{
	int			fpclass = class(x);

	if (fpclass == FP_PLUS_INF)
		return 1;
	if (fpclass == FP_MINUS_INF)
		return -1;
	return 0;
}

#endif