opensolaris man page for atanf

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(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+

SEE ALSO
       atan2(3M), isnan(3M), math.h(3HEAD), tan(3M), attributes(5), standards(5)

SunOS 5.11							    12 Jul 2006 							  atan(3M)