atan2 man page on Mageia

Man page or keyword search:  
man Server   17783 pages
apropos Keyword Search (all sections)
Output format
Mageia logo
[printable version]

ATAN2(3)		   Linux Programmer's Manual		      ATAN2(3)

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.

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       atan2f(), atan2l():
	      _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 ||
	      _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;
	      or cc -std=c99

DESCRIPTION
       The atan2() function calculates the principal value of the arc  tangent
       of  y/x, using the signs of the two arguments to determine the quadrant
       of the result.

RETURN VALUE
       On success, these functions return the principal value of the arc  tan‐
       gent of y/x in radians; the return value is in the range [-pi, pi].

       If y is +0 (-0) and x is less than 0, +pi (-pi) is returned.

       If y is +0 (-0) and x is greater than 0, +0 (-0) is returned.

       If y is less than 0 and x is +0 or -0, -pi/2 is returned.

       If y is greater than 0 and x is +0 or -0, pi/2 is returned.

       If either x or y is NaN, a NaN is returned.

       If y is +0 (-0) and x is -0, +pi (-pi) is returned.

       If y is +0 (-0) and x is +0, +0 (-0) is returned.

       If  y is a finite value greater (less) than 0, and x is negative infin‐
       ity, +pi (-pi) is returned.

       If y is a finite value greater (less) than 0, and x is positive	infin‐
       ity, +0 (-0) is returned.

       If  y  is  positive infinity (negative infinity), and x is finite, pi/2
       (-pi/2) is returned.

       If y is positive infinity (negative infinity) and x is negative	infin‐
       ity, +3*pi/4 (-3*pi/4) is returned.

       If  y is positive infinity (negative infinity) and x is positive infin‐
       ity, +pi/4 (-pi/4) is returned.

ERRORS
       No errors occur.

CONFORMING TO
       C99, POSIX.1-2001.  The variant returning double also conforms to SVr4,
       4.3BSD, C89.

SEE ALSO
       acos(3), asin(3), atan(3), carg(3), cos(3), sin(3), tan(3)

COLOPHON
       This  page  is  part of release 3.54 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

				  2010-09-20			      ATAN2(3)
[top]

List of man pages available for Mageia

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.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Tweet
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
...................................................................
Vote for polarhome
Free Shell Accounts :: the biggest list on the net