_finite, _finitel

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Header File

float.h

Prototype

int _finite(double d);
int _finitel(long double ld);

Description

Determines whether a given double-precision floating point value d is finite.

_finitel is the long double version; it takes a long double argument.

Return Value

Returns non-zero if the argument is finite, and 0 if it is not.

Portability

	POSIX	ANSI C	ANSI C++	Win32	Win64	macOS
_finite				+
_finitel				+

Example

#include <float.h>
#include <stdio.h>

/* Compare a and b if both have finite values */
int compare(double a, double b) {
	/* Only if both are finite. Otherwise give an indefinite ordering */
	if (_finite(a) && _finite(b)) {
		if (a < b)
			return -1;
		else if (a > b)
			return 1;
		else
			return 0;
	}
	else
		return -1;
}