TAN(3M) Mathematical Library Functions TAN(3M)

tan, tanf, tanl - tangent function

c99 [ flag... ] file... -lm [ library... ]
#include <math.h>
double tan(double x);

float tanf(float x);

long double tanl(long double x);

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

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.

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.

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.

See attributes(7) for descriptions of the following attributes:

Interface Stability Standard
MT-Level MT-Safe

math.h(3HEAD), atan(3M), feclearexcept(3M), fetestexcept(3M), isnan(3M), attributes(7), standards(7)

July 12, 2006 SunOS 5.11