COS

Section: Linux Programmer's Manual (3)
Updated: 2009-02-04
Index Return to Main Contents
 

NAME

cos, cosf, cosl - cosine function  

SYNOPSIS

#include <math.h>

double cos(double x);

float cosf(float x);
long double cosl(long double x);

Link with -lm.

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

cosf(), cosl(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE; or cc -std=c99  

DESCRIPTION

The cos() function returns the cosine of x, where x is given in radians.  

RETURN VALUE

On success, these functions return the cosine of x.

If x is a NaN, a NaN is returned.

If x is positive infinity or negative infinity, a domain error occurs, and a NaN is returned.  

ERRORS

See math_error(7) for information on how to determine whether an error has occurred when calling these functions.

The following errors can occur:

Domain error: x is an infinity
An invalid floating-point exception (FE_INVALID) is raised.

These functions do not set errno.  

CONFORMING TO

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

SEE ALSO

acos(3), asin(3), atan(3), atan2(3), ccos(3), sin(3), sincos(3), tan(3)  

COLOPHON

This page is part of release 3.22 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/.