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16 .\" manual page may be incorrect or out-of-date.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 2016-03-15 "" "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)):
76 || /* Since glibc 2.19: */ _DEFAULT_SOURCE
77 || /* Glibc versions <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE
87 _XOPEN_SOURCE \ >=\ 600
88 || (_ISOC99_SOURCE && _XOPEN_SOURCE)
89 || /* Since glibc 2.19: */ _DEFAULT_SOURCE
90 || /* Glibc versions <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE
99 functions return Bessel functions of
101 of the second kind of orders 0 and 1, respectively.
105 returns the Bessel function of
107 of the second kind of order
119 functions are versions that take and return
127 functions are versions that take and return
131 On success, these functions return the appropriate
132 Bessel value of the second kind for
137 is a NaN, a NaN is returned.
142 a domain error occurs,
143 and the functions return
149 (POSIX.1-2001 also allows a NaN return for this case.)
155 and the functions return
162 If the result underflows,
163 a range error occurs,
164 and the functions return 0.0
166 If the result overflows,
167 a range error occurs,
168 and the functions return
174 (POSIX.1-2001 also allows a 0.0 return for this case.)
178 for information on how to determine whether an error has occurred
179 when calling these functions.
181 The following errors can occur:
183 Domain error: \fIx\fP is negative
187 An invalid floating-point exception
191 Pole error: \fIx\fP is 0.0
192 .\" Before POSIX.1-2001 TC2, this was (inconsistently) specified
193 .\" as a range error.
196 .\" FIXME . y0(0.0) gives EDOM
201 exception is returned by
204 .\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6808
206 Range error: result underflow
207 .\" e.g., y0(1e33) on glibc 2.8/x86-32
211 .\" An underflow floating-point exception
212 .\" .RB ( FE_UNDERFLOW )
214 .\" FIXME . Is it intentional that these functions do not use FE_*?
215 .\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6806
218 exception is returned by
222 Range error: result overflow
223 .\" e.g., yn(10, 1e-40) on glibc 2.8/x86-32
228 is not set for this case.
229 .\" FIXME . Is it intentional that errno is not set?
230 .\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6808
231 An overflow floating-point exception
235 For an explanation of the terms used in this section, see
241 Interface Attribute Value
246 T} Thread safety MT-Safe
251 T} Thread safety MT-Safe
256 T} Thread safety MT-Safe
259 The functions returning
261 conform to SVr4, 4.3BSD,
262 POSIX.1-2001, POSIX.1-2008.
263 The others are nonstandard functions that also exist on the BSDs.
265 On a pole error, these functions set
271 as POSIX.1-2004 requires.
273 .\" Bug raised: http://sourceware.org/bugzilla/show_bug.cgi?id=6807
275 In glibc version 2.3.2 and earlier,
276 .\" FIXME . Actually, 2.3.2 is the earliest test result I have; so yet
277 .\" to confirm if this error occurs only in 2.3.2.
278 these functions do not raise an invalid floating-point exception
280 when a domain error occurs.