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[linuxjm/jm.git] / manual / LDP_man-pages / release / man7 / math_error.7

.\" Copyright (c) 2008, Linux Foundation, written by Michael Kerrisk
.\"     <mtk.manpages@gmail.com>
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein.  The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
.\" Japanese Version Copyright (c) 2008  Akihiro MOTOKI
.\"         all rights reserved.
.\" Translated 2008-08-17, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>, LDP v3.07
.\" 
.\"WORD:        significand     ²¾¿ôÉô
.\"WORD:        domain error    Îΰ襨¥é¡¼
.\"WORD:        pole error      ¶Ë¥¨¥é¡¼
.\"WORD:        range error     ÈÏ°Ï¥¨¥é¡¼
.\" 
.TH MATH_ERROR 7 2008-08-11 "Linux" "Linux Programmer's Manual"
.SH ̾Á°
math_error \- ¿ô³Ø´Ø¿ô¤«¤é¤Î¥¨¥é¡¼¤Î¸¡½Ð
.SH ½ñ¼°
.nf
.B #include <math.h>
.B #include <errno.h>
.B #include <fenv.h>
.fi
.SH ÀâÌÀ
¥¨¥é¡¼¤¬È¯À¸¤¹¤ë¤È¡¢¤Û¤È¤ó¤É¤Î¥é¥¤¥Ö¥é¥ê´Ø¿ô¤Ï (\-1 ¤ä NULL ¤Ê¤É¤Î)
ÆÃÊ̤ÊÃͤòÊÖ¤¹¤³¤È¤Ç¥¨¥é¡¼¤òÄÌÃΤ¹¤ë¡£
.I <math.h>
¤ÇÀë¸À¤µ¤ì¤Æ¤¤¤ë¿ô³Ø´Ø¿ô¤Ï¡¢Ä̾ï¤ÏÉâÆ°¾®¿ôÅÀÃͤòÊÖ¤¹¤Î¤Ç¡¢
¾¤Îµ¡¹½¤ò»È¤Ã¤Æ¥¨¥é¡¼¤òÄÌÃΤ¹¤ë¡£
¥¨¥é¡¼ÄÌÃε¡¹½¤Ï 2 ¼ïÎढ¤ê¡¢
¸Å¤¤¤â¤Î¤¬
.I errno
¤òÀßÄꤹ¤ë¤ä¤êÊý¤Ç¤¢¤ê¡¢¿·¤·¤¤¤â¤Î¤¬
.BR fenv (3)
¤ÇÀâÌÀ¤µ¤ì¤Æ¤¤¤ëÉâÆ°¾®¿ôÅÀÎã³°µ¡¹½¤Ç¤¢¤ë¡£
.RB ( feclearexcept (3)
¤È
.BR fetestexcept (3)
¤ò»ÈÍѤ¹¤ë¡£¤³¤ì¤é¤Ë¤Ä¤¤¤Æ¤Ï°Ê²¼¤Ç³µÍפòÀâÌÀ¤·¤Æ¤¤¤ë¡£)

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¿ô³Ø´Ø¿ô¤ò¸Æ¤Ó½Ð¤¹Á°¤Ë
.I errno
¤ò 0 ¤ËÀßÄꤷ¡¢°Ê²¼¤ò¸Æ¤Ó½Ð¤¹¤Ù¤­¤Ç¤¢¤ë¡£
.in +4n
.nf

feclearexcept(FE_ALL_EXCEPT);
.fi
.in

¿ô³Ø´Ø¿ô¤«¤éÊ֤äƤ­¤¿ºÝ¤Ë¡¢
.I errno
¤¬ 0 °Ê³°¤«¡¢°Ê²¼¤Î¸Æ¤Ó½Ð¤·¤¬ 0 °Ê³°¤òÊÖ¤·¤¿¾ì¹ç
.RB ( fenv (3)
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.in +4n
.nf

fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW |
             FE_UNDERFLOW);
.fi
.in
.\" enum
.\" {
.\" FE_INVALID = 0x01,
.\" __FE_DENORM = 0x02,
.\" FE_DIVBYZERO = 0x04,
.\" FE_OVERFLOW = 0x08,
.\" FE_UNDERFLOW = 0x10,
.\" FE_INEXACT = 0x20
.\" };

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.SS Îΰ襨¥é¡¼ (domain error)
.I Îΰ襨¥é¡¼
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Îΰè¤ËÆþ¤Ã¤Æ¤¤¤Ê¤¤¾ì¹ç¤Ç¤¢¤ë (Î㤨¤Ð
.BR log (3)
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¿ô³Ø´Ø¿ô¤ÏÉáÄÌ¤Ï NaN ¤òÊÖ¤·
(Ʊ¤¸¾õ¶·¤Ç°ã¤¦ÃͤòÊÖ¤¹´Ø¿ô¤â¤¢¤ë)¡¢
.I errno
¤Ë
.B EDOM
¤òÀßÄꤷ¡¢¡Ö̵¸ú (invalid)¡×
ÉâÆ°¾®¿ôÅÀÎã³°
.RB ( FE_INVALID )
¤ò¾å¤²¤ë¡£
.SS ¶Ë¥¨¥é¡¼ (pole error)
.I ¶Ë¥¨¥é¡¼
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(Î㤨¤Ð
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.BR HUGE_VAL ,
.BR HUGE_VALF ,
.B HUGE_VALL
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.IR float ,
.I "long double"
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.I errno
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.B ERANGE
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.RB ( FE_DIVBYZERO )
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.SS ÈÏ°Ï¥¨¥é¡¼ (range ¥¨¥é¡¼)
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.BR HUGE_VAL ,
.BR HUGE_VALF ,
.B HUGE_VALL
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¤½¤ì¤¾¤ì
.IR double ,
.IR float ,
.I "long double"
¤ËÂбþ¤¹¤ë)¡£
.I errno
¤Ï
.B ERANGE
¤ËÀßÄꤵ¤ì¡¢¡Ö¥ª¡¼¥Ð¡¼¥Õ¥í¡¼ (overflow)¡×
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.RB ( FE_OVERFLOW )
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.I errno
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.B ERANGE
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.SH Ãí°Õ
C99 ¤È POSIX.1-2001 ¤Çµ¬Äꤵ¤ì¤Æ¤¤¤ë
.I math_errhandling
¼±ÊÌ»Ò¤Ï glibc ¤Ç¤Ï¥µ¥Ý¡¼¥È¤µ¤ì¤Æ¤¤¤Ê¤¤¡£
.\" See CONFORMANCE in the glibc 2.8 (and earlier) source.
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.RI ( errno
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.BR fetestexcept (3)
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.I errno
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.I errno
¤È
.BR fetestexcept (3)
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ÊýË¡¤¬¿ä¾©¤µ¤ì¤Æ¤¤¤ë¡£
.\" http://www.securecoding.cert.org/confluence/display/seccode/FLP32-C.+Prevent+or+detect+domain+and+range+errors+in+math+functions
Î㤨¤Ð¡¢°Ê²¼¤Î¥³¡¼¥É¤Ï¡¢
.BR log (3)
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.in +4n
.nf

double x, r;

if (isnan(x) || islessequal(x, 0)) {
    /* Deal with NaN / pole error / domain error */
}

r = log(x);

.fi
.in
¤³¤Î¥Ú¡¼¥¸¤Ë½ñ¤«¤ì¤Æ¤¤¤ë¤³¤È¤Ï¡¢
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.BR gcc (1)
¤Î
.I "-fno-math-errno"
¥ª¥×¥·¥ç¥ó¤ò»È¤¦¤È¡¢¼Â¹Ô¥Õ¥¡¥¤¥ë¤Ç¡¢É¸½à¤Î¼ÂÁõ¤è¤ê¤â¹â®¤Ê¿ô³Ø´Ø¿ô¤Î
¼ÂÁõ¤¬»ÈÍѤµ¤ì¤ë¤è¤¦¤Ë¤Ê¤ë¤¬¡¢
¥¨¥é¡¼»þ¤Ë
.I errno
¤¬ÀßÄꤵ¤ì¤Ê¤¤
.RB ( gcc (1)
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.I "-ffast-math"
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.I "-fno-math-errno"
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.BR fetestexcept (3)
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.SH ´ØÏ¢¹àÌÜ
.BR gcc (1),
.BR errno (3),
.BR fenv (3),
.BR fpclassify (3),
.BR INFINITY (3),
.BR isgreater (3),
.BR matherr (3),
.BR nan (3)
.br
.I "info libc"