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);