#include <math.h> double log1p(double x);Link with -lm.
float log1pf(float x);
long double log1pl(long double x);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
log (1 + x)The result is computed in a way that is accurate even if the value of x is near zero.
If x is a NaN, a NaN is returned.
If x is positive infinity, positive infinity is returned.
If x is -1, a pole error occurs, and the functions return -HUGE_VAL, -HUGE_VALF, or -HUGE_VALL, respectively.
The following errors can occur:
|log1p(), log1pf(), log1pl()||Thread safety||MT-Safe|