Available in all subroutines.

Computes the hyperbolic cosine of its argument x.


x - Floating point value representing a hyperbolic angle.

Return Value

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

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

If x is ±0, the value 1.0 will be returned.

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

If the result would cause an overflow, a range error occurs and math.cosh will return the value of the macro math.POS_HUGE_VAL.


If the result would cause an overflow, then fastly.error will be set to ERANGE.


declare local FLOAT;
set = math.cosh(0);

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