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J0(3)                      Linux Programmer's Manual                     J0(3)
NAME
       j0,  j0f,  j0l,  j1,  j1f,  j1l, jn, jnf, jnl - Bessel functions of the
       first kind
SYNOPSIS
       #include <math.h>
       double j0(double x);
       double j1(double x);
       double jn(int n, double x);
       float j0f(float x);
       float j1f(float x);
       float jnf(int n, float x);
       long double j0l(long double x);
       long double j1l(long double x);
       long double jnl(int n, long double x);
       Link with -lm.
   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
       j0(), j1(), jn():
           _XOPEN_SOURCE
               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
               || /* Glibc versions <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE
       j0f(), j0l(), j1f(), j1l(), jnf(), jnl():
           _XOPEN_SOURCE  >= 600
               || (_ISOC99_SOURCE && _XOPEN_SOURCE)
               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
               || /* Glibc versions <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE
DESCRIPTION
       The j0() and j1() functions return Bessel functions of x of  the  first
       kind  of  orders  0 and 1, respectively.  The jn() function returns the
       Bessel function of x of the first kind of order n.
       The j0f(), j1f(), and jnf(),  functions  are  versions  that  take  and
       return  float  values.   The j0l(), j1l(), and jnl() functions are ver-
       sions that take and return long double values.
RETURN VALUE
       On success, these functions return the appropriate Bessel value of  the
       first kind for x.
       If x is a NaN, a NaN is returned.
       If x is too large in magnitude, or the result underflows, a range error
       occurs, and the return value is 0.
ERRORS
       See math_error(7) for information on how to determine whether an  error
       has occurred when calling these functions.
       The following errors can occur:
       Range error: result underflow, or x is too large in magnitude
              errno is set to ERANGE.
       These functions do not raise exceptions for fetestexcept(3).
ATTRIBUTES
       For   an   explanation   of   the  terms  used  in  this  section,  see
       attributes(7).
       +-------------------+---------------+---------+
       |Interface          | Attribute     | Value   |
       +-------------------+---------------+---------+
       |j0(), j0f(), j0l() | Thread safety | MT-Safe |
       +-------------------+---------------+---------+
       |j1(), j1f(), j1l() | Thread safety | MT-Safe |
       +-------------------+---------------+---------+
       |jn(), jnf(), jnl() | Thread safety | MT-Safe |
       +-------------------+---------------+---------+
CONFORMING TO
       The functions returning double conform to SVr4,  4.3BSD,  POSIX.1-2001,
       and POSIX.1-2008.  The others are nonstandard functions that also exist
       on the BSDs.
BUGS
       There are errors of up to 2e-16 in the values returned  by  j0(),  j1()
       and jn() for values of x between -8 and 8.
SEE ALSO
       y0(3)
COLOPHON
       This  page  is  part of release 4.15 of the Linux man-pages project.  A
       description of the project, information about reporting bugs,  and  the
       latest     version     of     this    page,    can    be    found    at
       https://www.kernel.org/doc/man-pages/.
                                  2017-09-15                             J0(3)