yn(3M)

NAME

     y0, y1, yn - Bessel functions of the second kind

SYNOPSIS

     cc [ flag ... ] file ... -lm [ library ... ]

     double y0(double x);

     double y1(double x);

     double yn(int n, double x);

DESCRIPTION

     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.

RETURN VALUES

     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.

ERRORS

     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.

USAGE

     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.

ATTRIBUTES

     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|

SEE ALSO

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