Available in all subroutines.

Computes the hyperbolic tangent of its argument x.


x - Floating point value representing a hyperbolic angle.

Return Value

Upon successful completion, this function returns the hyperbolic tangent of x.

If x is math.NAN, a NaN will be returned.

If x is ±0, x will be returned.

If x is math.POS_INFINITY or math.NEG_INFINITY, ±1 will be returned.

If x is subnormal, a range error occurs and x will be returned.


If the x argument is subnormal, then fastly.error will be set to ERANGE.


declare local FLOAT;
set = math.tanh(-1);

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