The y0(), y1() and yn() functions compute Bessel functions of x of the second kind of orders 0, 1 and n respectively. The value of x must be positive.

Upon successful completion, y0(), y1() and yn() will return the relevant Bessel value of x of the second kind.

If x is NaN, NaN is returned.

If the x argument to y0(), y1() or yn() is negative, -HUGE_VAL or NaN is returned, and errno may be set to EDOM.

If x is 0.0, -HUGE_VAL is returned and errno may be set to ERANGE or EDOM.

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

For exceptional cases, matherr(3M) tabulates the values to be returned as dictated by Standards other than XPG4.

The y0(), y1() and yn() functions may fail if:

EDOM

The value of x is negative.

ERANGE

The value of x is too large in magnitude, or x is 0.0, or the correct result would cause overflow.

An application wishing to check for error situations should set errno to 0 before calling y0(), y1() or yn(). If errno is non-zero on return, or the return value is NaN, an error has occurred.

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

isnan(3M), j0(3M), matherr(3M), attributes(5), standards(5)