ATAN(3) | Linux Programmer's Manual | ATAN(3) |
NAME
atan, atanf, atanl - arc tangent functionSYNOPSIS
#include<math.h>
double atan(double x );
float atanf(float x );
long double atanl( long double x );
Link with -lm.
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;
or
cc -std=c99
DESCRIPTION
The atan() function calculates the principal value of the arc tangent of x; that is the value whose tangent is x.RETURN VALUE
On success, these functions return the principal value of the arc tangent of x in radians; the return value is in the range [-pi/2, pi/2].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), atan2(3), carg(3), catan(3), cos(3), sin(3), tan(3)COLOPHON
This page is part of release 3.53 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 |