ATAN2

Section: Linux Programmer's Manual (3)
Updated: 2002-07-27
Index Return to Main Contents
 

NAME

atan2, atan2f, atan2l - arc tangent function of two variables  

SYNOPSIS

#include <math.h>

double atan2(double y, double x);

float atan2f(float y, float x);
long double atan2l(long double y, long double x);
Link with -lm.  

DESCRIPTION

The atan2() function calculates the arc tangent of the two variables x and y. It is similar to calculating the arc tangent of y / x, except that the signs of both arguments are used to determine the quadrant of the result.  

RETURN VALUE

The atan2() function returns the result in radians, which is between -PI and PI (inclusive).  

CONFORMING TO

SVr4, POSIX.1-2001, 4.3BSD, C89. The float and long double variants are C99 requirements.  

SEE ALSO

acos(3), asin(3), atan(3), cos(3), sin(3), tan(3)


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
CONFORMING TO
SEE ALSO

linux.jgfs.net manual pages