EXP

NAME

log, logf, logl - natural logarithmic function

#include <math.h>

double log(double x);

float logf(float x);

long double logl(long double x);

The log() function returns the natural logarithm of x.

The log() function can return the following errors:

EDOM: The argument x is negative.
ERANGE: The argument x is zero. The log of zero is not defined (minus infinity).

SVID 3, POSIX, BSD 4.3, ISO 9899. The float and the long double variants are C99 requirements.