HP C/iX Library Reference Manual (30026-90004)
Chapter 5 235
HP C/iX Library Function Descriptions
log, log10
log, log10
Syntax
#include <math.h>
double log (double
x
);
double log10 (double
y
);
Parameters
x
A real number whose natural logarithm is to be returned.
y
A real number whose logarithm in base 10 is to be returned.
Return Values
n The logarithm of the input value
x
.
-HUGE The input value
x
is ≤0, and errno is set to EDOM. A DOMAIN error or SING
error if
x
=0 is printed on the standard error output device.
Description
The log function returns the natural logarithm of
x
. The value of
x
must be positive.
The log10 function returns the logarithm base ten of
x
. The value of
x
must be positive.
Error handling can be changed by a user-written matherr function.
See Also
matherr(), ANSI C 4.5.4.4, POSIX.1 8.1