1 .\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de)
2 .\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk
3 .\" <mtk.manpages@gmail.com>
4 .\" Distributed under GPL
5 .\" Based on glibc infopages, copyright Free Software Foundation
7 .\" Japanese Version Copyright (c) 2002 Akihiro MOTOKI
8 .\" all rights reserved.
9 .\" Translated Sun Sep 22 09:46:55 2002
10 .\" by Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
11 .\" Updated 2008-09-16, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
13 .TH SIGNBIT 3 2008-08-05 "GNU" "Linux Programmer's Manual"
16 .\"O signbit \- test sign of a real floating-point number
17 signbit \- ÉâÆ°¾®¿ôÅÀ¼Â¿ô¤ÎÉä¹æ (sign) ¤òÄ´¤Ù¤ë
20 .B "#include <math.h>"
22 .BI "int signbit(" x ");"
24 .\"O Link with \fI\-lm\fP.
25 \fI\-lm\fP ¤Ç¥ê¥ó¥¯¤¹¤ë¡£
28 .\"O Feature Test Macro Requirements for glibc (see
29 .\"O .BR feature_test_macros (7)):
30 glibc ¸þ¤±¤Îµ¡Ç½¸¡ºº¥Þ¥¯¥í¤ÎÍ×·ï
31 .RB ( feature_test_macros (7)
37 _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE; or
43 .\"O is a generic macro which can work on all real floating-point types.
44 .\"O It returns a nonzero value if the value of
46 .\"O has its sign bit set.
48 ¤Ï¡¢¤¢¤é¤æ¤ë¼ïÎà¤ÎÉâÆ°¾®¿ôÅÀ¼Â¿ô¤ËÂФ·¤Æ
49 ŬÍѲÄǽ¤ÊÈÆÍÑŪ¤Ê¥Þ¥¯¥í¤Ç¤¢¤ë¡£
51 ¤ÎÃͤÎÉä¹æ¥Ó¥Ã¥È¤¬¥»¥Ã¥È¤µ¤ì¤Æ¤¤¤ë¾ì¹ç¡¢Èó 0 ¤ÎÃͤòÊÖ¤¹¡£
53 .\"O This is not the same as
55 .\"O because IEEE 754 floating point allows zero to be signed.
59 .\"O .IR "signbit(\-0.0)"
60 .\"O will return a nonzero value.
64 ¤Ê¤¼¤Ê¤é¡¢IEEE 754 ¤ÎÉâÆ°¾®¿ôÅÀɽ¸½¤Ç¤Ï 0 ¤âÉä¹æ¤ò»ý¤Ä¤«¤é¤Ç¤¢¤ë¡£
66 ¤È¤¤¤¦Èæ³Ó·ë²Ì¤Ïµ¶ (false) ¤À¤¬¡¢
70 .\"O NaNs and infinities have a sign bit.
71 NaN ¤È̵¸ÂÂç¤Ë¤ÏÉä¹æ¥Ó¥Ã¥È¤¬¤¢¤ë¡£
76 .\"O macro returns nonzero if the sign of
78 .\"O is negative; otherwise it returns zero.
82 ¤ÎÉä¹æ¤¬Éé¤Î¾ì¹ç 0 °Ê³°¤òÊÖ¤·¡¢¤½¤¦¤Ç¤Ê¤¤¾ì¹ç 0 ¤òÊÖ¤¹¡£
87 .\"O .SH "CONFORMING TO"
90 .\"O This function is defined in IEC 559 (and the appendix with
91 .\"O recommended functions in IEEE 754/IEEE 854).
92 ¤³¤Î´Ø¿ô¤Ï IEC 559 ¤ÇÄêµÁ¤µ¤ì¤Æ¤¤¤ë
93 (¤Þ¤¿ IEEE 754/IEEE 854 ¤Ç¤ÏÉÕÏ¿¤Ç¿ä¾©´Ø¿ô¤È¤·¤ÆÄêµÁ¤µ¤ì¤Æ¤¤¤ë)¡£