cos

, cosf

, cosl

- cosine function

Synopsis

c99 [ flag... ] file... -lm [ library... ]
#include <math.h>

double cos(double x);

float cosf(float x);

long double cosl(long double x);

Description

These functions compute the cosine of x, measured in radians.

Return Values

Upon successful completion, these functions return the cosine of x.

If x is NaN, NaN is returned.

If x is +0, 1.0 is returned.

If x is ±Inf, a domain error occurs and a NaN is returned.

Errors

These functions will fail if:

Domain Error

The x argument is ±Inf.

If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, the invalid floating-point exception is raised.

Usage

An application wanting to check for exceptions should call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an exception has been raised. An application should either examine the return value or check the floating point exception flags to detect exceptions.

Attributes

See attributes(5) for descriptions of the following attributes:

See Also

acos(3M), feclearexcept(3M), fetestexcept(3M), isnan(3M), math.h(3HEAD), sin(3M), tan(3M), attributes(5), standards(5)