log1p(), log1pf()

Log(1+x)

Synopsis:

#include <math.h>

double log1p ( double x );

float log1pf ( float x );

libm

The log1p() and log1pf() functions compute the value of log(1+x), where x > -1.0.

If x is:	log1p() returns:
NAN	NAN
x < `-1.0`	-HUGE_VAL, or NAN (errno is set to EDOM).
x = `-1.0`	-HUGE_VAL (errno may be set to ERANGE).