log1p
, log1pf
—log of 1 +
x#include <math.h> double log1p(double x); float log1pf(float x);
Description
log1p
calculates
the natural logarithm of 1+
x. You can use log1p
rather
than `log(1+
x)
' for greater precision when x is very
small.
log1pf
calculates the same thing, but accepts and returns
float
values rather than double
.
Returns
log1p
returns a double
, the natural log of 1+
x.
log1pf
returns a float
, the natural log of 1+
x.
Portability
Neither log1p
nor log1pf
is required by ANSI C or by the System V
Interface Definition (Issue 2).