y0l

       ond kind

SYNOPSIS
       #include <math.h>

       double y0(double x);
       double y1(double x);
       double yn(int n, double x);

       float y0f(float x);
       float y1f(float x);
       float ynf(int n, float x);

       long double y0l(long double x);
       long double y1l(long double x);
       long double ynl(int n, long double x);

       Link with -lm.

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       y0(), y1(), yn(): _SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCE
       y0f(), y0l(), y1f(), y1l(), ynf(), ynl(): _SVID_SOURCE || _BSD_SOURCE
       || _XOPEN_SOURCE >= 600

DESCRIPTION
       The  y0() and y1() functions return Bessel functions of x of the second
       kind of orders 0 and 1, respectively.  The yn()  function  returns  the
       Bessel function of x of the second kind of order n.

       The value of x must be positive.

       The  y0f()  etc.  and  y0l()  etc. functions are versions that take and
       return float and long double values, respectively.

RETURN VALUE
       On success, these functions return the appropriate Bessel value of  the
       second kind for x.

       If x is a NaN, a NaN is returned.

       If  x  is  negative,  a  domain  error occurs, and the functions return
       -HUGE_VAL, -HUGE_VALF, or -HUGE_VALL, respectively.  (POSIX.1-2001 also
       allows a NaN return for this case.)

       If  x  is 0.0, a pole error occurs, and the functions return -HUGE_VAL,
       -HUGE_VALF, or -HUGE_VALL, respectively.

       If the result underflows, a  range  error  occurs,  and  the  functions
       return 0.0

       If the result overflows, a range error occurs, and the functions return
       -HUGE_VAL, -HUGE_VALF, or -HUGE_VALL, respectively.  (POSIX.1-2001 also
       allows a 0.0 return for this case.)
              errno  is  set to ERANGE (but see BUGS).  No FE_DIVBYZERO excep-
              tion is returned by fetestexcept(3) for this case.

       Range error: result underflow
              errno is set to ERANGE.  No FE_UNDERFLOW exception  is  returned
              by fetestexcept(3) for this case.

       Range error: result overflow
              errno  is  not  set  for  this case.  An overflow floating-point
              exception (FE_OVERFLOW) is raised.

CONFORMING TO
       The functions returning double conform to SVr4,  4.3BSD,  POSIX.1-2001.
       The others are non-standard functions that also exist on the BSDs.

BUGS
       On  a  pole error, these functions set errno to EDOM, instead of ERANGE
       as POSIX.1-2004 requires.

       In glibc version 2.3.2 and earlier, these functions  do  not  raise  an
       invalid  floating-point  exception  (FE_INVALID)  when  a  domain error
       occurs.

SEE ALSO
       j0(3)

COLOPHON
       This page is part of release 3.23 of the Linux  man-pages  project.   A
       description  of  the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.



                                  2008-08-10                             Y0(3)