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
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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16 .\" manual page may be incorrect or out-of-date.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
97 of the second kind of orders 0 and 1, respectively.
101 returns the Bessel function of
103 of the second kind of order
114 etc. functions are versions that take and return
118 values, respectively.
120 On success, these functions return the appropriate
121 Bessel value of the second kind for
126 is a NaN, a NaN is returned.
131 a domain error occurs,
132 and the functions return
138 (POSIX.1-2001 also allows a NaN return for this case.)
144 and the functions return
151 If the result underflows,
152 a range error occurs,
153 and the functions return 0.0
155 If the result overflows,
156 a range error occurs,
157 and the functions return
163 (POSIX.1-2001 also allows a 0.0 return for this case.)
167 for information on how to determine whether an error has occurred
168 when calling these functions.
170 The following errors can occur:
172 Domain error: \fIx\fP is negative
176 An invalid floating-point exception
180 Pole error: \fIx\fP is 0.0
181 .\" Before POSIX.1-2001 TC2, this was (inconsistently) specified
182 .\" as a range error.
185 .\" FIXME . y0(0.0) gives EDOM
190 exception is returned by
193 .\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6808
195 Range error: result underflow
196 .\" e.g., y0(1e33) on glibc 2.8/x86-32
200 .\" An underflow floating-point exception
201 .\" .RB ( FE_UNDERFLOW )
203 .\" FIXME . Is it intentional that these functions do not use FE_*?
204 .\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6806
207 exception is returned by
211 Range error: result overflow
212 .\" e.g., yn(10, 1e-40) on glibc 2.8/x86-32
217 is not set for this case.
218 .\" FIXME . Is it intentional that errno is not set?
219 .\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6808
220 An overflow floating-point exception
224 The functions returning
226 conform to SVr4, 4.3BSD,
228 The others are nonstandard functions that also exist on the BSDs.
230 On a pole error, these functions set
236 as POSIX.1-2004 requires.
238 .\" Bug raised: http://sourceware.org/bugzilla/show_bug.cgi?id=6807
240 In glibc version 2.3.2 and earlier,
241 .\" FIXME . Actually, 2.3.2 is the earliest test result I have; so yet
242 .\" to confirm if this error occurs only in 2.3.2.
243 these functions do not raise an invalid floating-point exception
245 when a domain error occurs.