tan

, tanf

, tanl

- tangent function

Synopsis

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

double tan(double x);

float tanf(float x);

long double tanl(long double x);

Description

These functions compute the tangent of their argument x, measured in radians.

Return Values

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

If x is NaN, a NaN is returned.

If x is ±0, x is returned.

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

Errors

These functions will fail if:

Domain Error

The value of x is ±Inf.

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

Usage

There are no known floating-point representations such that for a normal argument, tan(x) is either overflow or underflow.

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

atan(3M), feclearexcept(3M), fetestexcept(3M), isnan(3M), math.h(3HEAD), attributes(5), standards(5)