1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
2 .\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk
3 .\" <mtk.manpages@gmail.com>
5 .\" %%%LICENSE_START(VERBATIM)
6 .\" Permission is granted to make and distribute verbatim copies of this
7 .\" manual provided the copyright notice and this permission notice are
8 .\" preserved on all copies.
10 .\" Permission is granted to copy and distribute modified versions of this
11 .\" manual under the conditions for verbatim copying, provided that the
12 .\" entire resulting derived work is distributed under the terms of a
13 .\" permission notice identical to this one.
15 .\" Since the Linux kernel and libraries are constantly changing, this
16 .\" manual page may be incorrect or out-of-date. The author(s) assume no
17 .\" responsibility for errors or omissions, or for damages resulting from
18 .\" the use of the information contained herein. The author(s) may not
19 .\" have taken the same level of care in the production of this manual,
20 .\" which is licensed free of charge, as they might when working
23 .\" Formatted or processed versions of this manual, if unaccompanied by
24 .\" the source, must acknowledge the copyright and authors of this work.
27 .\" References consulted:
28 .\" Linux libc source code
29 .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
31 .\" Modified Sat Jul 24 19:08:17 1993 by Rik Faith (faith@cs.unc.edu)
32 .\" Modified 2002-08-25, aeb
33 .\" Modified 2004-11-12 as per suggestion by Fabian Kreutz/AEB
34 .\" 2008-07-24, mtk, created this page, based on material from j0.3.
36 .TH Y0 3 2008-08-10 "" "Linux Programmer's Manual"
38 y0, y0f, y0l, y1, y1f, y1l, yn, ynf, ynl \-
39 Bessel functions of the second kind
44 .BI "double y0(double " x );
46 .BI "double y1(double " x );
48 .BI "double yn(int " n ", double " x );
50 .BI "float y0f(float " x );
52 .BI "float y1f(float " x );
54 .BI "float ynf(int " n ", float " x );
56 .BI "long double y0l(long double " x );
58 .BI "long double y1l(long double " x );
60 .BI "long double ynl(int " n ", long double " x );
66 Feature Test Macro Requirements for glibc (see
67 .BR feature_test_macros (7)):
75 _SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCE
85 _SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCE\ >=\ 600
86 .\" Also seems to work: -std=c99 -D_XOPEN_SOURCE
95 functions return Bessel functions of \fIx\fP
96 of the second kind of orders 0 and 1, respectively.
100 returns the Bessel function of \fIx\fP of the second kind of order \fIn\fP.
102 The value of \fIx\fP must be positive.
108 etc. functions are versions that take and return
112 values, respectively.
114 On success, these functions return the appropriate
115 Bessel value of the second kind for
120 is a NaN, a NaN is returned.
125 a domain error occurs,
126 and the functions return
132 (POSIX.1-2001 also allows a NaN return for this case.)
138 and the functions return
145 If the result underflows,
146 a range error occurs,
147 and the functions return 0.0
149 If the result overflows,
150 a range error occurs,
151 and the functions return
157 (POSIX.1-2001 also allows a 0.0 return for this case.)
161 for information on how to determine whether an error has occurred
162 when calling these functions.
164 The following errors can occur:
166 Domain error: \fIx\fP is negative
170 An invalid floating-point exception
174 Pole error: \fIx\fP is 0.0
175 .\" Before POSIX.1-2001 TC2, this was (inconsistently) specified
176 .\" as a range error.
179 .\" FIXME . y0(0.0) gives EDOM
184 exception is returned by
187 .\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6808
189 Range error: result underflow
190 .\" e.g., y0(1e33) on glibc 2.8/x86-32
194 .\" An underflow floating-point exception
195 .\" .RB ( FE_UNDERFLOW )
197 .\" FIXME . Is it intentional that these functions do not use FE_*?
198 .\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6806
201 exception is returned by
205 Range error: result overflow
206 .\" e.g., yn(10, 1e-40) on glibc 2.8/x86-32
211 is not set for this case.
212 .\" FIXME . Is it intentional that errno is not set?
213 .\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6808
214 An overflow floating-point exception
218 The functions returning
220 conform to SVr4, 4.3BSD,
222 The others are nonstandard functions that also exist on the BSDs.
224 On a pole error, these functions set
230 as POSIX.1-2004 requires.
232 .\" Bug raised: http://sourceware.org/bugzilla/show_bug.cgi?id=6807
234 In glibc version 2.3.2 and earlier,
235 .\" FIXME . Actually, 2.3.2 is the earliest test result I have; so yet
236 .\" to confirm if this error occurs only in 2.3.2.
237 these functions do not raise an invalid floating-point exception
239 when a domain error occurs.