The hypot() function computes the length of the hypotenuse of a right-angled triangle:

Upon successful completion, hypot() returns the length of the hypotenuse of a right angled triangle with sides of length x and y.

If the result would cause overflow, HUGE_VAL is returned and errno may be set to ERANGE.

If x or y is NaN, NaN is returned.

The hypot() function may fail if:

ERANGE

The result overflows.

The hypot() function takes precautions against underflow and overflow during intermediate steps of the computation.

An application wishing to check for error situations should set errno to 0 before calling hypot(). If errno is non-zero on return, or the return value is HUGE_VAL or NaN, an error has occurred.

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

isnan(3M), sqrt(3M), attributes(5)