1 .\" Copyright 1995 Jim Van Zandt <jrv@vanzandt.mv.com>
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15 .\" manual page may be incorrect or out-of-date.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 .\" Modified 2002-07-27 by Walter Harms
26 .\" (walter.harms@informatik.uni-oldenburg.de)
28 .\" Japanese Version Copyright (c) 2003 Akihiro MOTOKI
29 .\" all rights reserved.
30 .\" Translated Wed Aug 6 00:35:20 JST 2003
31 .\" by Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
32 .\" Updated 2008-09-16, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
34 .TH LOG1P 3 2010-09-20 "" "Linux Programmer's Manual"
37 .\"O log1p, log1pf, log1pl \- logarithm of 1 plus argument
38 log1p, log1pf, log1pl \- 引き数に 1 を加えた値の対数
44 .BI "double log1p(double " x );
46 .BI "float log1pf(float " x );
48 .BI "long double log1pl(long double " x );
51 .\"O Link with \fI\-lm\fP.
55 .\"O Feature Test Macro Requirements for glibc (see
56 .\"O .BR feature_test_macros (7)):
58 .RB ( feature_test_macros (7)
65 _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 500 ||
66 _XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED || _ISOC99_SOURCE ||
67 _POSIX_C_SOURCE\ >=\ 200112L;
76 _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE ||
77 _POSIX_C_SOURCE\ >=\ 200112L;
86 .\"O returns a value equivalent to
94 .\"O It is computed in a way
95 .\"O that is accurate even if the value of \fIx\fP is near zero.
96 \fIx\fP の値が 0 に近い場合でも正確に計算できる方法が用いられる。
99 .\"O On success, these functions return the natural logarithm of
100 .\"O .IR "(1\ +\ x)" .
108 .\"O a NaN is returned.
114 .\"O is positive infinity, positive infinity is returned.
116 が正の無限大の場合、正の無限大が返される。
120 .\"O is \-1, a pole error occurs,
121 .\"O and the functions return
122 .\"O .RB - HUGE_VAL ,
123 .\"O .RB - HUGE_VALF ,
125 .\"O .RB - HUGE_VALL ,
128 が \-1 の場合、極エラー (pole error) が発生し、
137 .\"O is less than \-1 (including negative infinity),
138 .\"O a domain error occurs,
139 .\"O and a NaN (not a number) is returned.
141 が \-1 より小さい場合 (負の無限大も含む)、
142 領域エラー (domain error) が発生し、
143 NaN (not a number) が返される。
144 .\" POSIX.1 specifies a possible range error if x is subnormal
145 .\" glibc 2.8 doesn't do this
149 .\"O .BR math_error (7)
150 .\"O for information on how to determine whether an error has occurred
151 .\"O when calling these functions.
152 これらの関数を呼び出した際にエラーが発生したかの判定方法についての情報は
156 .\"O The following errors can occur:
159 .\"O Domain error: \fIx\fP is less than \-1
160 領域エラー (domain error): \fIx\fP が \-1 より小さい
164 .\"O An invalid floating-point exception
165 .\"O .RB ( FE_INVALID )
171 .\"O Pole error: \fIx\fP is \-1
172 極エラー (pole error): \fIx\fP が \-1 である
176 .\"O A divide-by-zero floating-point exception
177 .\"O .RB ( FE_DIVBYZERO )
179 0 による除算 (divide-by-zero) 浮動小数点例外
183 .\"O These functions do not set
188 .\" FIXME . Is it intentional that these functions do not set errno?
189 .\" log(), log2(), log10() do set errno
190 .\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6792
191 .\"O .SH "CONFORMING TO"