_logb, _logbl

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Header File

float.h

Prototype

double _logb(double d);
long double _logbl(long double ld);

Description

Extracts the exponential value of a double-precision floating-point argument. If the argument is denormalized, it is treated as if it were normalized.

_logbl is the long double version; it takes a long double argument and returns a long double result.

Return Value

Returns the unbiased exponent of the value passed in.

	POSIX	ANSI C	ANSI C++	Win32	Win64	OS X
_logb				+
_logbl				+

Example

#include <math.h>
#include <stdio.h>

int main(void) {
	double result;
	double x = 8.6872;

	result = _logb(x);

	printf("The natural log of %lf is %lf\n", x, result);
	return 0;
}