# atan2(3m) [opensolaris man page]

atan2(3M) Mathematical Library Functions atan2(3M)NAME

atan2, atan2f, atan2l - arc tangent functionSYNOPSIS

c99 [ flag... ] file...[ library... ] #include <math.h> double atan2(double y, double x); float atan2f(float y, float x); long double atan2l(long double y, long double x);-lmDESCRIPTION

These functions compute the principal value of the arc tangent of y/x, using the signs of both arguments to determine the quadrant of the return value.RETURN VALUES

Upon successful completion, these functions return the arc tangent of y/x in the range [,pi ] radians. If y is +-0 and x is < 0, +-pi is returned. If y is +-0 and x is > 0, +-0 is returned. If y is < 0 and x is +-0, -pi/2 is returned. If y is > 0 and x is +-0, pi/2 is returned. If x is 0, a pole error does not occur. If either x or y is NaN, a NaN is returned. If y is +-0 and x is-pi, +-pi is returned. If y is +-0 and x is +0, +-0 is returned. For finite values of +-y > 0, if x is-0, +-pi is returned. For finite values of +-y > 0, if x is +Inf, +-0 is returned. For finite values of x, if y is +-Inf, +-pi/2 is returned. If y is +-Inf and x is-Inf, +-3pi/4 is returned. If y is +-Inf and x is +Inf, +-pi/4 is returned. If both arguments are 0, a domain error does not occur.-InfERRORS

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

atan(3M), isnan(3M), math.h(3HEAD)tan(3M), attributes(5), standards(5)SunOS 5.1112 Jul 2006 atan2(3M)

## Check Out this Related Man Page

NAME

atan2, atan2f, atan2l - arc tangent functionSYNOPSIS

c99 [ flag... ] file...[ library... ] #include <math.h> double atan2(double y, double x); float atan2f(float y, float x); long double atan2l(long double y, long double x);-lmDESCRIPTION

These functions compute the principal value of the arc tangent of y/x, using the signs of both arguments to determine the quadrant of the return value.RETURN VALUES

Upon successful completion, these functions return the arc tangent of y/x in the range [,pi ] radians. If y is +-0 and x is < 0, +-pi is returned. If y is +-0 and x is > 0, +-0 is returned. If y is < 0 and x is +-0, -pi/2 is returned. If y is > 0 and x is +-0, pi/2 is returned. If x is 0, a pole error does not occur. If either x or y is NaN, a NaN is returned. If y is +-0 and x is-pi, +-pi is returned. If y is +-0 and x is +0, +-0 is returned. For finite values of +-y > 0, if x is-0, +-pi is returned. For finite values of +-y > 0, if x is +Inf, +-0 is returned. For finite values of x, if y is +-Inf, +-pi/2 is returned. If y is +-Inf and x is-Inf, +-3pi/4 is returned. If y is +-Inf and x is +Inf, +-pi/4 is returned. If both arguments are 0, a domain error does not occur.-InfERRORS

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

atan(3M), isnan(3M), math.h(3HEAD)tan(3M), attributes(5), standards(5)SunOS 5.1112 Jul 2006 atan2(3M)