expm1,
expm1f
[exponential minus 1]
SYNOPSIS
#include <math.h>
double expm1(double x);
float expm1f(float x);
DESCRIPTION
expm1
and expm1f
calculate the exponential of x
and subtract 1, that is, ex
– 1 (where e is the base of the natural system of logarithms, approximately
2.71828).
The result is accurate even for small values of x, where using exp(x)-1 would lose many significant digits.
RETURNS
ex – 1.
COMPLIANCE
Neither expm1
nor expm1f
is required by ANSI C or by the System
V Interface Definition (Issue 2).