Compute Bessel functions of the first kind.

    This function is supported on OpenVMS Integrity servers and
    Alpha only.

    Format

      #include  <math.h>

      double j0  (double x);

      float j0f  (float x);

      long double j0l  (long double x);

      double j1  (double x);

      float j1f  (float x);

      long double j1l  (long double x);

      double jn  (int n, double x);

      float jnf  (int n, float x);

      long double jnl  (int n, long double x);

1  –  Arguments

 x

    A real value.

 n

    An integer.

2  –  Description

    The j0 functions return the value of the Bessel function of the
    first kind of order 0.

    The j1 functions return the value of the Bessel function of the
    first kind of order 1.

    The jn functions return the value of the Bessel function of the
    first kind of order n.

    The j1 and jn functions can result in an underflow as x gets
    small. The largest value of x for which this occurs is a function
    of n.

3  –  Return Values

    x                  The relevant Bessel value of x of the first
                       kind.
    0                  The value of the x argument is too large, or
                       underflow occurred; errno is set to ERANGE.
    NaN                x is NaN; errno is set to EDOM.