

double log( double x )
double x; /* a double value */



Synopsis 
#include "math.h"
The log function calculates the natural logarithm of x , for x greater than 0.


Parameters 
x is a double greater than 0.


Return Value 
log returns the computed value if x is greater than 0. Otherwise, if x is negative log sets errno (the system error variable) to EDOM , or if x is 0, log sets errno to ERANGE . log returns a value equal to the negative of HUGE_VAL (approximately 1.79769e+308) in both error cases.


See Also 



