log1p, log1pf, log1pl - compute natural logarithm

Definition	#include <math.h> double log1p(double x); float log1pf(double x); (C11) long double log1p(long double x); (C11) These functions compute loge (1.0 + x), where x must be greater than -1.0.
Return val.	ln(1.0 + x)	if successful.
	-HUGE_VAL -HUGE_VALF -HUGE_VALL	depending on the function type, if x is less than or equal to -1. In addition, errno is set to EDOM (domain error).
See also	log