NAME

log1p - logarithm of 1 plus argument

SYNOPSIS

#include <math.h>

double log1p(double x);

float log1pf(float x);

long double log1pl(long double x);

Link with -lm.

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

log1p(), log1pf(), log1pl(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 || _ISOC99_SOURCE; or cc -std=c99

DESCRIPTION

log1p(x) returns a value equivalent to `log (1 + x)'. It is computed in a way that is accurate even if the value of x is near zero.

CONFORMING TO

BSD, C99. The float and long double variants are C99 requirements.

SEE ALSO

exp(3), expm1(3), log(3)