log functions
[Syntax]
double log(double x)
float logf(float x)
long double logl(long double x) [V2.01.00 or later]
[Description]
These functions calculate the natural logarithm of x with e as the base.
[Special case]
Condition
Return value
Exception
x<0
NaN
EDOM
x==0
-∞
ERANGE