atan2l man page on MacOSX

 Man page or keyword search:   man All Sections 1 - General Commands 2 - System Calls 3 - Subroutines, Functions 4 - Special Files 5 - File Formats 6 - Games and Screensavers 7 - Macros and Conventions 8 - Maintenence Commands 9 - Kernel Interface New Commands Server 4.4BSD AIX Alpinelinux Archlinux Aros BSDOS BSDi Bifrost CentOS Cygwin Darwin Debian DigitalUNIX DragonFly ElementaryOS Fedora FreeBSD Gentoo GhostBSD HP-UX Haiku Hurd IRIX Inferno JazzOS Kali Knoppix LinuxMint MacOSX Mageia Mandriva Manjaro Minix MirBSD NeXTSTEP NetBSD OPENSTEP OSF1 OpenBSD OpenDarwin OpenIndiana OpenMandriva OpenServer OpenSuSE OpenVMS Oracle PC-BSD Peanut Pidora Plan9 QNX Raspbian RedHat Scientific Slackware SmartOS Solaris SuSE SunOS Syllable Tru64 UNIXv7 Ubuntu Ultrix UnixWare Xenix YellowDog aLinux   23457 pages apropos Keyword Search (all sections) Output format html ascii pdf view pdf save postscript
[printable version]

```ATAN2(3)		 BSD Library Functions Manual		      ATAN2(3)

NAME
atan2 — arc tangent function of two variables

SYNOPSIS
#include <math.h>

double
atan2(double y, double x);

long double
atan2l(long double y, long double x);

float
atan2f(float y, float x);

DESCRIPTION
The atan2() function computes the principal value of the arc tangent of
y/x, using the signs of both arguments to determine the quadrant of the
return value.

SPECIAL VALUES
atan2(�0, -0) returns �pi.

atan2(�0, +0) returns �0.

atan2(�0, x) returns �pi for x < 0.

atan2(�0, x) returns �0 for x > 0.

atan2(y, �0) returns +pi/2 for y > 0.

atan2(y, �0) returns -pi/2 for y < 0.

atan2(�y, -infinity) returns �pi for finite y > 0.

atan2(�y, +infinity) returns �0 for finite y > 0.

atan2(�infinity, x) returns �pi/2 for finite x.

atan2(�infinity, -infinity) returns �3*pi/4.

atan2(�infinity, +infinity) returns �pi/4.

NOTES
The atan2() function is used mostly to convert from rectangular (x,y) to
polar (r,theta) coordinates that must satisfy x = r∗cos theta and y =
r∗sin theta.  In general, conversions to polar coordinates should be com‐
puted thus:

r	:= hypot(x,y);	... := sqrt(x∗x+y∗y)
theta     := atan2(y,x).

VECTOR OPERATIONS
If you need to apply the atan2() function to SIMD vectors or arrays,
using the following functions provided by the Accelerate.framework may
give significantly better performance:

#include <Accelerate/Accelerate.h>

vFloat atan2f(vFloat y, vFloat x);
void vvatan2f(float *z, const float *y, const float *x, const int *n);
void vvatan2(double *z, const double *y, const double *x, const int *n);

acos(3), asin(3), atan(3), cos(3), cosh(3), sin(3), sinh(3), tan(3),
tanh(3), math(3),

STANDARDS
The atan2() function conforms to ISO/IEC 9899:2011.

BSD			       December 11, 2006			   BSD
```
[top]

List of man pages available for MacOSX

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.