The j0(), j1() and jn() functions compute Bessel functions of x of the first kind of orders 0, 1 and n respectively.

Upon successful completion, j0(), j1() and jn() return the relevant Bessel value of x of the first kind.

If the x argument is too large in magnitude, 0 is returned and errno may be set to ERANGE.

If x is NaN, NaN is returned.

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

The j0(), j1() and jn() functions may fail if:

ERANGE

The value of x was too large in magnitude.

An application wishing to check for error situations should set errno to 0 before calling j0(), j1() or jn(). 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), matherr(3M), y0(3M), attributes(5), standards(5)