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 .\" Permission is granted to make and distribute verbatim copies of this
6 .\" manual provided the copyright notice and this permission notice are
7 .\" preserved on all copies.
9 .\" Permission is granted to copy and distribute modified versions of this
10 .\" manual under the conditions for verbatim copying, provided that the
11 .\" entire resulting derived work is distributed under the terms of a
12 .\" permission notice identical to this one.
14 .\" Since the Linux kernel and libraries are constantly changing, this
15 .\" manual page may be incorrect or out-of-date. The author(s) assume no
16 .\" responsibility for errors or omissions, or for damages resulting from
17 .\" the use of the information contained herein. The author(s) may not
18 .\" have taken the same level of care in the production of this manual,
19 .\" which is licensed free of charge, as they might when working
22 .\" Formatted or processed versions of this manual, if unaccompanied by
23 .\" the source, must acknowledge the copyright and authors of this work.
25 .\" References consulted:
26 .\" Linux libc source code
27 .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
29 .\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu)
30 .\" Modified 1995-08-14 by Arnt Gulbrandsen <agulbra@troll.no>
31 .\" Modified 2002-07-27 by Walter Harms
32 .\" (walter.harms@informatik.uni-oldenburg.de)
34 .\" Japanese Version Copyright (c) 2003, 2008 Akihiro MOTOKI
35 .\" all rights reserved.
36 .\" Translated Mon Sep 7 23:27:52 JST 2003
37 .\" by Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
38 .\" Updated 2008-09-18, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
40 .TH POW 3 2008-08-10 "" "Linux Programmer's Manual"
42 pow, powf, powl \- Îß¾è´Ø¿ô
47 .BI "double pow(double " x ", double " y );
49 .BI "float powf(float " x ", float " y );
51 .BI "long double powl(long double " x ", long double " y );
54 \fI\-lm\fP ¤Ç¥ê¥ó¥¯¤¹¤ë¡£
57 glibc ¸þ¤±¤Îµ¡Ç½¸¡ºº¥Þ¥¯¥í¤ÎÍ×·ï
58 .RB ( feature_test_macros (7)
65 _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE; or
70 ´Ø¿ô¤Ï \fIx\fP ¤Î \fIy\fP ¾è¤ÎÃͤòÊÖ¤¹¡£
72 À®¸ù¤¹¤ë¤È¡¢¤³¤ì¤é¤Î´Ø¿ô¤Ï
81 ¤¬À°¿ô¤Ç¤Ê¤¤Í¸ÂÃͤξì¹ç¡¢Îΰ襨¥é¡¼ (domain error) ¤¬È¯À¸¤·¡¢
82 .\" The domain error is generated at least as far back as glibc 2.4
85 ·ë²Ì¤¬¥ª¡¼¥Ð¡¼¥Õ¥í¡¼¤¹¤ë¾ì¹ç¡¢
86 ÈÏ°Ï¥¨¥é¡¼ (range error) ¤¬È¯À¸¤·¡¢
87 .\" The range error is generated at least as far back as glibc 2.4
92 ¤òÊÖ¤¹¡£ÊÖ¤êÃͤˤϿô³ØŪ¤ËÀµ¤·¤¤Éä¹æ¤¬ÉÕÍ¿¤µ¤ì¤ë¡£
94 ·ë²Ì¤¬¥¢¥ó¥À¡¼¥Õ¥í¡¼¤·¡¢¤½¤ÎÃͤ¬É½¸½²Äǽ¤Ç¤Ê¤¤¾ì¹ç¡¢
95 ÈÏ°Ï¥¨¥é¡¼¤¬È¯À¸¤·¡¢ 0.0 ¤¬ÊÖ¤µ¤ì¤ë¡£
96 .\" POSIX.1 does not specify the sign of the zero,
97 .\" but http://sources.redhat.com/bugzilla/show_bug.cgi?id=2678
98 .\" points out that the zero has the wrong sign in some cases.
100 °Ê²¼¤Çµ¬Äꤵ¤ì¤Æ¤¤¤Ê¤¤¾ì¹ç¤Ç¡¢
104 ¤¬ NaN ¤Î¾ì¹ç¡¢ÊÖ¤êÃÍ¤Ï NaN ¤È¤Ê¤ë¡£
109 ¤¬ NaN ¤Ç¤¢¤Ã¤¿¤È¤·¤Æ¤â) ÊÖ¤êÃÍ¤Ï 1.0 ¤È¤Ê¤ë¡£
114 ¤¬ NaN ¤Ç¤¢¤Ã¤¿¤È¤·¤Æ¤â) ÊÖ¤êÃÍ¤Ï 1.0 ¤È¤Ê¤ë¡£
119 ¤¬ 0 ¤è¤êÂ礤ʴñ¿ô¤Î¾ì¹ç¡¢ÊÖ¤êÃÍ¤Ï +0 (\-0) ¤È¤Ê¤ë¡£
124 ¤¬ 0 ¤è¤êÂ礤¯´ñ¿ô¤Ç¤Ê¤¤¾ì¹ç¡¢ÊÖ¤êÃÍ¤Ï +0 ¤È¤Ê¤ë¡£
129 ¤¬Àµ¤Î̵¸ÂÂ礫Éé¤Î̵¸ÂÂç¤Î¾ì¹ç¡¢ÊÖ¤êÃÍ¤Ï 1.0 ¤È¤Ê¤ë¡£
132 ¤ÎÀäÂÐÃͤ¬ 1 ̤Ëþ¤Ç¡¢
134 ¤¬Éé¤Î̵¸ÂÂç¤Î¾ì¹ç¡¢ÊÖ¤êÃͤÏÀµ¤Î̵¸ÂÂç¤È¤Ê¤ë¡£
137 ÀäÂÐÃͤ¬ 1 ¤è¤êÂ礤¯¡¢
139 ¤¬Éé¤Î̵¸ÂÂç¤Î¾ì¹ç¡¢ÊÖ¤êÃÍ¤Ï +0 ¤È¤Ê¤ë¡£
142 ¤ÎÀäÂÐÃͤ¬ 1 ̤Ëþ¤Ç¡¢
144 ¤¬Àµ¤Î̵¸ÂÂç¤Î¾ì¹ç¡¢ÊÖ¤êÃÍ¤Ï +0 ¤È¤Ê¤ë¡£
147 ¤ÎÀäÂÐÃͤ¬ 1 ¤è¤êÂ礤¯¡¢
149 ¤¬Àµ¤Î̵¸ÂÂç¤Î¾ì¹ç¡¢ÊÖ¤êÃͤÏÀµ¤Î̵¸ÂÂç¤È¤Ê¤ë¡£
154 ¤¬ 0 ¤è¤ê¾®¤µ¤¤´ñ¿ô¤Î¾ì¹ç¡¢ÊÖ¤êÃÍ¤Ï \-0 ¤È¤Ê¤ë¡£
159 ¤¬ 0 ¤è¤ê¾®¤µ¤¯´ñ¿ô¤Ç¤Ê¤¤¾ì¹ç¡¢ÊÖ¤êÃÍ¤Ï +0 ¤È¤Ê¤ë¡£
164 ¤¬ 0 ¤è¤êÂ礤¤´ñ¿ô¤Î¾ì¹ç¡¢ÊÖ¤êÃͤÏÉé¤Î̵¸ÂÂç¤È¤Ê¤ë¡£
169 ¤¬ 0 ¤è¤êÂ礤¯´ñ¿ô¤Ç¤Ê¤¤¾ì¹ç¡¢ÊÖ¤êÃͤÏÀµ¤Î̵¸ÂÂç¤È¤Ê¤ë¡£
174 ¤¬ 0 ̤Ëþ¤Î¾ì¹ç¡¢ÊÖ¤êÃÍ¤Ï +0 ¤È¤Ê¤ë¡£
179 ¤¬ 0 ¤è¤êÂ礤¤¾ì¹ç¡¢ÊÖ¤êÃͤÏÀµ¤Î̵¸ÂÂç¤È¤Ê¤ë¡£
184 ¤¬ 0 ¤è¤ê¾®¤µ¤¤´ñ¿ô¤Î¾ì¹ç¡¢
185 ¶Ë¥¨¥é¡¼ (pole error) ¤¬È¯À¸¤·¡¢ÊÖ¤êÃͤÏ
191 ¤ÈƱ¤¸Éä¹æ¤¬ÉÕÍ¿¤µ¤ì¤ë¡£
196 ¤¬ 0 ¤è¤ê¾®¤µ¤¯´ñ¿ô¤Ç¤Ê¤¤¾ì¹ç¡¢
198 .\" The pole error is generated at least as far back as glibc 2.4
205 .\" FIXME . review status of this error
206 .\" longstanding bug report for glibc:
207 .\" http://sources.redhat.com/bugzilla/show_bug.cgi?id=369
208 .\" For negative x, and -large and +large y, glibc 2.8 gives incorrect
210 .\" pow(-0.5,-DBL_MAX)=nan
211 .\" EDOM FE_INVALID nan; fail-errno fail-except fail-result;
212 .\" FAIL (expected: range-error-overflow (ERANGE, FE_OVERFLOW); +INF)
214 .\" pow(-1.5,-DBL_MAX)=nan
215 .\" EDOM FE_INVALID nan; fail-errno fail-except fail-result;
216 .\" FAIL (expected: range-error-underflow (ERANGE, FE_UNDERFLOW); +0)
218 .\" pow(-0.5,DBL_MAX)=nan
219 .\" EDOM FE_INVALID nan; fail-errno fail-except fail-result;
220 .\" FAIL (expected: range-error-underflow (ERANGE, FE_UNDERFLOW); +0)
222 .\" pow(-1.5,DBL_MAX)=nan
223 .\" EDOM FE_INVALID nan; fail-errno fail-except fail-result;
224 .\" FAIL (expected: range-error-overflow (ERANGE, FE_OVERFLOW); +INF)
225 ¤³¤ì¤é¤Î´Ø¿ô¤ò¸Æ¤Ó½Ð¤·¤¿ºÝ¤Ë¥¨¥é¡¼¤¬È¯À¸¤·¤¿¤«¤ÎȽÄêÊýË¡¤Ë¤Ä¤¤¤Æ¤Î¾ðÊó¤Ï
229 °Ê²¼¤Î¥¨¥é¡¼¤¬È¯À¸¤¹¤ë²ÄǽÀ¤¬¤¢¤ë¡£
231 Îΰ襨¥é¡¼: \fIx\fP ¤¬Éé¤Ç¡¢\fIy\fP ¤¬À°¿ô¤Ç¤Ê¤¤Í¸ÂÃÍ
236 ÉÔÀµ (invalid) ÉâÆ°¾®¿ôÅÀÎã³°
240 ¶Ë¥¨¥é¡¼: \fIx\fP ¤¬¥¼¥í¤Ç¡¢\fIy\fP ¤¬Éé
245 .\" FIXME . glibc 2.8 gives EDOM
246 0 ¤Ë¤è¤ë½ü»» (divide-by-zero) ÉâÆ°¾®¿ôÅÀÎã³°
250 ÈÏ°Ï¥¨¥é¡¼: ·ë²Ì¤¬¥ª¡¼¥Ð¡¼¥Õ¥í¡¼
255 ¥ª¡¼¥Ð¡¼¥Õ¥í¡¼ÉâÆ°¾®¿ôÅÀÎã³°
259 ÈÏ°Ï¥¨¥é¡¼: ·ë²Ì¤¬¥¢¥ó¥À¡¼¥Õ¥í¡¼
264 ¥¢¥ó¥À¡¼¥Õ¥í¡¼ÉâÆ°¾®¿ôÅÀÎã³°
270 ÈǤδؿô¤Ï SVr4, 4.3BSD, C89 ¤Ë¤â½àµò¤·¤Æ¤¤¤ë¡£
274 .\" FIXME . this is as at glibc 2.8; check later if this bug is fixed
275 .\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6776
282 ¤òÀßÄꤹ¤Ù¤¤È¤µ¤ì¤Æ¤¤¤ë¡£
285 ¤¬Éé¤Î¾ì¹ç¡¢Â礤ÊÀµÉé¤ÎÃͤÎ
287 ¤¬Í¿¤¨¤é¤ì¤ë¤È¡¢´Ø¿ô¤Î·ë²Ì¤¬ NaN ¤È¤Ê¤ê¡¢
299 ¤ÎÀäÂÐÃͤ¬Ìó 9.223373e18 ¤è¤êÂ礤¤¾ì¹ç¤Ë¤³¤Î¾õ¶·¤È¤Ê¤ë¡£
300 .\" see bug http://sources.redhat.com/bugzilla/show_bug.cgi?id=3866
301 .\" and http://sources.redhat.com/bugzilla/show_bug.cgi?id=369
303 glibc ¥Ð¡¼¥¸¥ç¥ó 2.3.2 °ÊÁ°¤Ç¤Ï¡¢
304 .\" FIXME . Actually, 2.3.2 is the earliest test result I have; so yet
305 .\" to confirm if this error occurs only in 2.3.2.
306 ¥¢¥ó¥À¡¼¥Õ¥í¡¼¤ä¥¢¥ó¥À¡¼¥Õ¥í¡¼¤Î¥¨¥é¡¼¤¬È¯À¸¤¹¤ë¾ì¹ç¡¢
309 ¤Ï¡¢¥ª¡¼¥Ð¡¼¥Õ¥í¡¼Îã³°¤ä¥¢¥ó¥À¡¼¥Õ¥í¡¼Îã³°¤ò¾å¤²¤ë¤À¤±¤Ç¤Ê¤¯¡¢