ATAN(3M) Mathematical Library Functions ATAN(3M)
NAME
atan, atanf, atanl - arc tangent function
SYNOPSIS
c99 [
flag... ]
file...
-lm [
library... ]
#include <math.h>
double atan(
double x);
float atanf(
float x);
long double atanl(
long double x);
DESCRIPTION
These functions compute the principal value of the arc tangent of
x.
RETURN VALUES
Upon successful completion, these functions return the arc tangent of
x in the range [-pi/2,pi/2] radians.
If
x is NaN, NaN is returned.
If x is +-0,
x is returned.
If
x is +-Inf, +-pi/2 is returned.
ERRORS
No errors are defined.
ATTRIBUTES
See
attributes(7) for descriptions of the following attributes:
+----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+----------------------------+-----------------------------+
|Interface Stability | Standard |
+----------------------------+-----------------------------+
|MT-Level | MT-Safe |
+----------------------------+-----------------------------+
SEE ALSO
math.h(3HEAD),
atan2(3M),
isnan(3M),
tan(3M),
attributes(7),
standards(7)SunOS 5.11 July 12, 2006 ATAN(3M)
