Computes loge(1.0 + xx).

#include <math.h>

double log1p (double x);

Return Values

Upon successful completion, this function shall return the natural logarithm of 1.0 + x.

If x is -1, a pole error shall occur and log1p() shall return -HUGE_VAL.

For finite values of x that are less than -1, or if x is -Inf, a domain error shall occur, and a NaN shall be returned.

If x is NaN, a NaN shall be returned.

If x is +/-0, or +Inf, x shall be returned.

If x is subnormal, a range error may occur and x should be returned.

Requirements