man-pages/man3/y0.3.html
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<H1>Y0</H1>
Section: Linux Programmer's Manual (3)<BR>Updated: 2017-09-15<BR><A HREF="#index">Index</A>
<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
<A NAME="lbAB">&nbsp;</A>
<H2>NAME</H2>
y0, y0f, y0l, y1, y1f, y1l, yn, ynf, ynl -
Bessel functions of the second kind
<A NAME="lbAC">&nbsp;</A>
<H2>SYNOPSIS</H2>
<PRE>
<B>#include &lt;<A HREF="file:///usr/include/math.h">math.h</A>&gt;</B>
<B>double y0(double </B><I>x</I><B>);</B>
<B>double y1(double </B><I>x</I><B>);</B>
<B>double yn(int </B><I>n</I><B>, double </B><I>x</I><B>);</B>
<B>float y0f(float </B><I>x</I><B>);</B>
<B>float y1f(float </B><I>x</I><B>);</B>
<B>float ynf(int </B><I>n</I><B>, float </B><I>x</I><B>);</B>
<B>long double y0l(long double </B><I>x</I><B>);</B>
<B>long double y1l(long double </B><I>x</I><B>);</B>
<B>long double ynl(int </B><I>n</I><B>, long double </B><I>x</I><B>);</B>
</PRE>
<P>
Link with <I>-lm</I>.
<P>
Feature Test Macro Requirements for glibc (see
<B><A HREF="/cgi-bin/man/man2html?7+feature_test_macros">feature_test_macros</A></B>(7)):
<P>
<B>y0</B>(),
<B>y1</B>(),
<B>yn</B>():
<DL COMPACT><DT id="1"><DD>
_XOPEN_SOURCE
<BR>&nbsp;&nbsp;&nbsp;&nbsp;||&nbsp;/*&nbsp;Since&nbsp;glibc&nbsp;2.19:&nbsp;*/&nbsp;_DEFAULT_SOURCE
<BR>&nbsp;&nbsp;&nbsp;&nbsp;||&nbsp;/*&nbsp;Glibc&nbsp;versions&nbsp;&lt;=&nbsp;2.19:&nbsp;*/&nbsp;_SVID_SOURCE&nbsp;||&nbsp;_BSD_SOURCE
</DL>
<BR>
<B>y0f</B>(),
<B>y0l</B>(),
<B>y1f</B>(),
<B>y1l</B>(),
<B>ynf</B>(),
<B>ynl</B>():
<DL COMPACT><DT id="2"><DD>
_XOPEN_SOURCE &nbsp;&gt;=&nbsp;600
<BR>&nbsp;&nbsp;&nbsp;&nbsp;||&nbsp;(_ISOC99_SOURCE&nbsp;&amp;&amp;&nbsp;_XOPEN_SOURCE)
<BR>&nbsp;&nbsp;&nbsp;&nbsp;||&nbsp;/*&nbsp;Since&nbsp;glibc&nbsp;2.19:&nbsp;*/&nbsp;_DEFAULT_SOURCE
<BR>&nbsp;&nbsp;&nbsp;&nbsp;||&nbsp;/*&nbsp;Glibc&nbsp;versions&nbsp;&lt;=&nbsp;2.19:&nbsp;*/&nbsp;_SVID_SOURCE&nbsp;||&nbsp;_BSD_SOURCE
</DL>
<A NAME="lbAD">&nbsp;</A>
<H2>DESCRIPTION</H2>
<P>
The
<B>y0</B>()
and
<B>y1</B>()
functions return Bessel functions of
<I>x</I>
of the second kind of orders 0 and 1, respectively.
The
<B>yn</B>()
function
returns the Bessel function of
<I>x</I>
of the second kind of order
<I>n</I>.
<P>
The value of
<I>x</I>
must be positive.
<P>
The
<B>y0f</B>(),
<B>y1f</B>(),
and
<B>ynf</B>()
functions are versions that take and return
<I>float</I>
values.
The
<B>y0l</B>(),
<B>y1l</B>(),
and
<B>ynl</B>()
functions are versions that take and return
<I>long double</I>
values.
<A NAME="lbAE">&nbsp;</A>
<H2>RETURN VALUE</H2>
On success, these functions return the appropriate
Bessel value of the second kind for
<I>x</I>.
<P>
If
<I>x</I>
is a NaN, a NaN is returned.
<P>
If
<I>x</I>
is negative,
a domain error occurs,
and the functions return
-<B>HUGE_VAL</B>,
-<B>HUGE_VALF</B>,
or
-<B>HUGE_VALL</B>,
respectively.
(POSIX.1-2001 also allows a NaN return for this case.)
<P>
If
<I>x</I>
is 0.0,
a pole error occurs,
and the functions return
-<B>HUGE_VAL</B>,
-<B>HUGE_VALF</B>,
or
-<B>HUGE_VALL</B>,
respectively.
<P>
If the result underflows,
a range error occurs,
and the functions return 0.0
<P>
If the result overflows,
a range error occurs,
and the functions return
-<B>HUGE_VAL</B>,
-<B>HUGE_VALF</B>,
or
-<B>HUGE_VALL</B>,
respectively.
(POSIX.1-2001 also allows a 0.0 return for this case.)
<A NAME="lbAF">&nbsp;</A>
<H2>ERRORS</H2>
See
<B><A HREF="/cgi-bin/man/man2html?7+math_error">math_error</A></B>(7)
for information on how to determine whether an error has occurred
when calling these functions.
<P>
The following errors can occur:
<DL COMPACT>
<DT id="3">Domain error: <I>x</I> is negative<DD>
<I>errno</I>
is set to
<B>EDOM</B>.
An invalid floating-point exception
(<B>FE_INVALID</B>)
is raised.
<DT id="4">Pole error: <I>x</I> is 0.0<DD>
<I>errno</I>
is set to
<B>ERANGE</B>
(but see BUGS).
No
<B>FE_DIVBYZERO</B>
exception is returned by
<B><A HREF="/cgi-bin/man/man2html?3+fetestexcept">fetestexcept</A></B>(3)
for this case.
<DT id="5">Range error: result underflow<DD>
<I>errno</I>
is set to
<B>ERANGE</B>.
No
<B>FE_UNDERFLOW</B>
exception is returned by
<B><A HREF="/cgi-bin/man/man2html?3+fetestexcept">fetestexcept</A></B>(3)
for this case.
<DT id="6">Range error: result overflow<DD>
<I>errno</I>
is not set for this case.
An overflow floating-point exception
(<B>FE_OVERFLOW</B>)
is raised.
</DL>
<A NAME="lbAG">&nbsp;</A>
<H2>ATTRIBUTES</H2>
For an explanation of the terms used in this section, see
<B><A HREF="/cgi-bin/man/man2html?7+attributes">attributes</A></B>(7).
<TABLE BORDER>
<TR VALIGN=top><TD><B>Interface</B></TD><TD><B>Attribute</B></TD><TD><B>Value</B><BR></TD></TR>
<TR VALIGN=top><TD>
<B>y0</B>(),
<B>y0f</B>(),
<B>y0l</B>()
</TD><TD>Thread safety</TD><TD>MT-Safe<BR></TD></TR>
<TR VALIGN=top><TD>
<B>y1</B>(),
<B>y1f</B>(),
<B>y1l</B>()
</TD><TD>Thread safety</TD><TD>MT-Safe<BR></TD></TR>
<TR VALIGN=top><TD>
<B>yn</B>(),
<B>ynf</B>(),
<B>ynl</B>()
</TD><TD>Thread safety</TD><TD>MT-Safe<BR></TD></TR>
</TABLE>
<A NAME="lbAH">&nbsp;</A>
<H2>CONFORMING TO</H2>
The functions returning
<I>double</I>
conform to SVr4, 4.3BSD,
POSIX.1-2001, POSIX.1-2008.
The others are nonstandard functions that also exist on the BSDs.
<A NAME="lbAI">&nbsp;</A>
<H2>BUGS</H2>
On a pole error, these functions set
<I>errno</I>
to
<B>EDOM</B>,
instead of
<B>ERANGE</B>
as POSIX.1-2004 requires.
<P>
In glibc version 2.3.2 and earlier,
these functions do not raise an invalid floating-point exception
(<B>FE_INVALID</B>)
when a domain error occurs.
<A NAME="lbAJ">&nbsp;</A>
<H2>SEE ALSO</H2>
<B><A HREF="/cgi-bin/man/man2html?3+j0">j0</A></B>(3)
<A NAME="lbAK">&nbsp;</A>
<H2>COLOPHON</H2>
This page is part of release 5.05 of the Linux
<I>man-pages</I>
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
<A HREF="https://www.kernel.org/doc/man-pages/.">https://www.kernel.org/doc/man-pages/.</A>
<P>
<HR>
<A NAME="index">&nbsp;</A><H2>Index</H2>
<DL>
<DT id="7"><A HREF="#lbAB">NAME</A><DD>
<DT id="8"><A HREF="#lbAC">SYNOPSIS</A><DD>
<DT id="9"><A HREF="#lbAD">DESCRIPTION</A><DD>
<DT id="10"><A HREF="#lbAE">RETURN VALUE</A><DD>
<DT id="11"><A HREF="#lbAF">ERRORS</A><DD>
<DT id="12"><A HREF="#lbAG">ATTRIBUTES</A><DD>
<DT id="13"><A HREF="#lbAH">CONFORMING TO</A><DD>
<DT id="14"><A HREF="#lbAI">BUGS</A><DD>
<DT id="15"><A HREF="#lbAJ">SEE ALSO</A><DD>
<DT id="16"><A HREF="#lbAK">COLOPHON</A><DD>
</DL>
<HR>
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Time: 00:06:01 GMT, March 31, 2021
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