(split) LDP_man-pages: release ioctl.2 [JM:00378]

[linuxjm/LDP_man-pages.git] / draft / man3 / strtod.3

.\" Copyright (c) 1990, 1991 The Regents of the University of California.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" the American National Standards Committee X3, on Information
.\" Processing Systems.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"     This product includes software developed by the University of
.\"     California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)strtod.3    5.3 (Berkeley) 6/29/91
.\"
.\" Modified Sun Aug 21 17:16:22 1994 by Rik Faith (faith@cs.unc.edu)
.\" Modified Sat May 04 19:34:31 MET DST 1996 by Michael Haardt
.\"   (michael@cantor.informatik.rwth-aachen.de)
.\" Added strof, strtold, aeb, 2001-06-07
.\"
.\" Japanese Version Copyright (c) 1998-1999
.\"   Michihide Hotta and NAKANO Takeo all rights reserved.
.\" Translated Fri Jun 26 1998 by Yasushi Shoji <yashi@yashi.com>
.\" Updated & Modified Sun Mar 14 1999 by NAKANO Takeo <nakano@apm.seikei.ac.jp>
.\" Updated & Modified Sun Jul  1 16:59:53 JST 2001
.\"         by Yuichi SATO <ysato@h4.dion.ne.jp>
.\" Updated & Modified 2006-07-20,
.\"         Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>, LDP v2.36
.\"
.TH STRTOD 3 2010-00-20 "Linux" "Linux Programmer's Manual"
.\"O .SH NAME
.\"O strtod, strtof, strtold \- convert ASCII string to floating-point number
.SH ̾Á°
strtod, strtof, strtold \- ASCII ʸ»úÎó¤òÉâÆ°¾®¿ôÅÀ¼Â¿ô¤ËÊÑ´¹¤¹¤ë
.\"O .SH SYNOPSIS
.SH ½ñ¼°
.B #include <stdlib.h>
.sp
.BI "double strtod(const char *" nptr ", char **" endptr );
.br
.BI "float strtof(const char *" nptr ", char **" endptr );
.br
.BI "long double strtold(const char *" nptr ", char **" endptr );
.sp
.in -4n
.\"O Feature Test Macro Requirements for glibc (see
.\"O .BR feature_test_macros (7)):
glibc ¸þ¤±¤Îµ¡Ç½¸¡ºº¥Þ¥¯¥í¤ÎÍ×·ï
.RB ( feature_test_macros (7)
»²¾È):
.in
.ad l
.sp
.BR strtof (),
.BR strtold ():
.RS 4
_XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE\ >=\ 200112L;
.br
or
.I cc\ -std=c99
.RE
.ad l
.\"O .SH DESCRIPTION
.SH ÀâÌÀ
.\"O The
.\"O .BR strtod (),
.\"O .BR strtof (),
.\"O and
.\"O .BR strtold ()
.\"O functions convert the initial portion of the string pointed to by
.\"O .I nptr
.\"O to
.\"O .IR double ,
.\"O .IR float ,
.\"O and
.\"O .I long double
.\"O representation, respectively.
.BR strtod (),
.BR strtof (),
.BR strtold ()
´Ø¿ô¤Ï¡¢
.I nptr
¤¬»Ø¤·¼¨¤¹Ê¸»úÎó¤Î¤Ï¤¸¤á¤ÎÉôʬ¤ò
.IR double ,
.IR float ,
.I long double
·¿¤ÎÃͤˤ½¤ì¤¾¤ìÊÑ´¹¤¹¤ë¡£

.\"O The expected form of the (initial portion of the) string is
.\"O optional leading white space as recognized by
.\"O .BR isspace (3),
.\"O an optional plus (\(aq+\(aq) or minus sign (\(aq\-\(aq) and then either
.\"O (i) a decimal number, or (ii) a hexadecimal number,
.\"O or (iii) an infinity, or (iv) a NAN (not-a-number).
ÆþÎϤ¹¤ëʸ»úÎó (¤ÎÀèƬÉôʬ) ¤Ï°Ê²¼¤Î·Á¼°¤¬´üÂÔ¤µ¤ì¤Æ¤¤¤ë¡£
ÀèƬ¤Ë¥Û¥ï¥¤¥È¥¹¥Ú¡¼¥¹¡¢
¼¡¤Ë¥×¥é¥¹ (\(aq+\(aq) ¤Þ¤¿¤Ï¥Þ¥¤¥Ê¥¹ (\(aq\-\(aq) ¤Îµ­¹æ¡¢
¤½¤Î¸å¤Ë (i) 10 ¿Ê¿ô¡¢(ii) 16 ¿Ê¿ô¡¢(iii) ̵¸Â¡¢
(iv) NAN (·×»»¤Ç¤­¤Ê¤¤¿ô¡¢not-a-number) ¤Î¤¤¤º¤ì¤«¤¬¤¢¤ë
(¥Û¥ï¥¤¥È¥¹¥Ú¡¼¥¹¡¢Éä¹æ¤Ï¾Êά²Äǽ¡£
¥Û¥ï¥¤¥È¥¹¥Ú¡¼¥¹¤Ï
.BR isspace (3)
¤Ç¼±Ê̤µ¤ì¤ë)¡£
.LP
.\"O A
.\"O .I "decimal number"
.\"O consists of a nonempty sequence of decimal digits
.\"O possibly containing a radix character (decimal point, locale-dependent,
.\"O usually \(aq.\(aq), optionally followed by a decimal exponent.
.\"O A decimal exponent consists of an \(aqE\(aq or \(aqe\(aq, followed by an
.\"O optional plus or minus sign, followed by a nonempty sequence of
.\"O decimal digits, and indicates multiplication by a power of 10.
.I "10 ¿Ê¿ô"
¤Ï 1 ʸ»ú°Ê¾å¤Î 10 ¿Ê¤Î¿ô»ú¤ÎÎ󤫤é¤Ê¤ê¡¢
´ð¤òɽ¤¹Ê¸»ú (radix charater)
(¾®¿ôÅÀ¡£¥í¥±¡¼¥ë¤Ë°Í¸¤¹¤ë¤¬¡¢Ä̾ï¤Ï \(aq.\(aq) ¤¬´Þ¤Þ¤ì¤ë¤³¤È¤â¤¢¤ë¡£
¤³¤Î¸å¤Ë 10 ¿Ê¤Î»Ø¿ôÉô¤¬Â³¤¤¤Æ¤âÎɤ¤¡£
10 ¿Ê¤Î»Ø¿ôÉô¤Ï \(aqE\(aq ¤Þ¤¿¤Ï \(aqe\(aq ¤È¡¢¤½¤Î¸å¤ËÃÖ¤«¤ì¤ëÀµÉéµ­¹æ (¾Êά²Ä)¡¢
¤ª¤è¤Ó¤½¤Î¸å¤Ë³¤¯ 1 ʸ»ú°Ê¾å¤Î 10 ¿Ê¤Î¿ô»ú¤ÎÎ󤫤é¤Ê¤ê¡¢
10 ¤Î²¿¾è¤Ç¤¢¤ë¤«¤òɽ¤¹¡£
.LP
.\"O A
.\"O .I "hexadecimal number"
.\"O consists of a "0x" or "0X" followed by a nonempty sequence of
.\"O hexadecimal digits possibly containing a radix character,
.\"O optionally followed by a binary exponent.
.\"O A binary exponent
.\"O consists of a \(aqP\(aq or \(aqp\(aq, followed by an optional
.\"O plus or minus sign, followed by a nonempty sequence of
.\"O decimal digits, and indicates multiplication by a power of 2.
.\"O At least one of radix character and binary exponent must be present.
.I "16 ¿Ê¿ô"
¤Ï¡¢"0x" ¤Þ¤¿¤Ï "0X" ¤È¤½¤Î¸å¤Ë³¤¯ 1 ʸ»ú°Ê¾å¤Î 16 ¿Ê¤Î¿ô»ú¤ÎÎ󤫤é¤Ê¤ê¡¢
´ð¤òɽ¤¹Ê¸»ú¤¬´Þ¤Þ¤ì¤ë¤³¤È¤â¤¢¤ë¡£
¤³¤Î¸å¤Ë 2 ¿Ê¤Î»Ø¿ôÉô¤¬Â³¤¤¤Æ¤âÎɤ¤¡£
2 ¿Ê¤Î»Ø¿ôÉô¤Ï \(aqP\(aq ¤Þ¤¿¤Ï \(aqp\(aq ¤È¡¢¤½¤Î¸å¤ËÃÖ¤«¤ì¤ëÀµÉéµ­¹æ (¾Êά²Ä)¡¢
¤ª¤è¤Ó¤½¤Î¸å¤Ë³¤¯ 1 ʸ»ú°Ê¾å¤Î 10 ¿Ê¤Î¿ô»ú¤ÎÎ󤫤鹽À®¤µ¤ì¡¢
2 ¤Î²¿¾è¤Ç¤¢¤ë¤«¤òɽ¤¹¡£
´ð¤òɽ¤¹Ê¸»ú¤È 2 ¿Ê¤Î»Ø¿ôÉô¤Ï¡¢¤É¤Á¤é¤«°ìÊý¤·¤«Â¸ºß¤·¤Æ¤Ï¤Ê¤é¤Ê¤¤¡£
.LP
.\"O An
.\"O .I infinity
.\"O is either "INF" or "INFINITY", disregarding case.
.I ̵¸Â
¤Ï "INF" ¤Þ¤¿¤Ï "INFINITY" ¤Çɽ¤µ¤ì¡¢Âçʸ»ú¾®Ê¸»ú¤Ï¶èÊ̤µ¤ì¤Ê¤¤¡£
.LP
.\"O A
.\"O .I NAN
.\"O is "NAN" (disregarding case) optionally followed by \(aq(\(aq,
.\"O a sequence of characters, followed by \(aq)\(aq.
.\"O The character string specifies in an implementation-dependent
.\"O way the type of NAN.
.I NAN
¤Ï "NAN" (Âçʸ»ú¾®Ê¸»ú¤Ï¶èÊ̤µ¤ì¤Ê¤¤) ¤Çɽ¤µ¤ì¡¢
¤½¤Î¸å¤Ë \(aq(\(aq ʸ»úÎó \(aq)\(aq ¤¬Â³¤¯¾ì¹ç¤â¤¢¤ë¡£
¤³¤Îʸ»úÎó¤Ï¼ÂÁõ¤Ë°Í¸¤¹¤ë NAN ¤ò»ØÄꤹ¤ë¡£
.\" From glibc 2.8's stdlib/strtod_l.c:
.\"     We expect it to be a number which is put in the
.\"     mantissa of the number.
.\"O .SH "RETURN VALUES"
.SH ÊÖ¤êÃÍ
.\"O These functions return the converted value, if any.
¤³¤ì¤é¤Î´Ø¿ô¤Ï¡¢ÊÑ´¹¤µ¤ì¤¿Ãͤ¬¤¢¤ì¤Ð¡¢¤½¤ì¤òÊÖ¤¹¡£

.\"O If
.\"O .I endptr
.\"O is not NULL,
.\"O a pointer to the character after the last character used in the conversion
.\"O is stored in the location referenced by
.\"O .IR endptr .
.I endptr
¤¬ NULL ¤Ç¤Ê¤¤¤È¤­¤Ï¡¢ÊÑ´¹¤Ë»È¤ï¤ì¤¿ºÇ½ªÊ¸»ú¤Î¼¡¤Îʸ»ú¤Ø¤Î¥Ý¥¤¥ó¥¿¡¼¤¬
.I endptr
¤Ç»²¾È¤µ¤ì¤ë¾ì½ê¤ØÊݸ¤µ¤ì¤ë¡£

.\"O If no conversion is performed, zero is returned and the value of
.\"O .I nptr
.\"O is stored in the location referenced by
.\"O .IR endptr .
ÊÑ´¹¤¬¹Ô¤ï¤ì¤Ê¤«¤Ã¤¿¤È¤­¤Ë¤Ï 0 ¤¬Ê֤롣¤½¤·¤Æ
.I endptr
¤¬»²¾È¤·¤Æ¤¤¤ë¾ì½ê¤Ë
.I nptr
¤ÎÃÍ (ÊÑ´¹ÂоݤǤ¢¤ëʸ»úÎó¤Î³«»Ï¥¢¥É¥ì¥¹) ¤¬Êݸ¤µ¤ì¤ë¡£

.\"O If the correct value would cause overflow, plus or minus
.\"O .B HUGE_VAL
.\"O .RB ( HUGE_VALF ,
.\"O .BR HUGE_VALL )
.\"O is returned (according to the sign of the value), and
.\"O .B ERANGE
.\"O is stored in
.\"O .IR errno .
.\"O If the correct value would cause underflow, zero is
.\"O returned and
.\"O .B ERANGE
.\"O is stored in
.\"O .IR errno .
Àµ¤·¤¤·Á¼°¤Î¿ôÃÍʸ»úÎó¤Ç¤¢¤ë¤¬¡¢ÊÑ´¹·ë²Ì¤¬¥ª¡¼¥Ð¡¼¥Õ¥í¡¼¤òµ¯¤³¤·¤¿¾ì¹ç
¤Ë¤Ï¡¢¥×¥é¥¹¤Þ¤¿¤Ï¥Þ¥¤¥Ê¥¹¤Î
.B HUGE_VAL
.RB ( HUGE_VALF ,
.BR HUGE_VALL )
¤¬ÊÖ¤ê (ÃͤÎÉä¹æ¤Ë¤è¤ë)¡¢
.B ERANGE
¤¬
.I errno
¤ËÂåÆþ¤µ¤ì¤ë¡£ÊÑ´¹·ë²Ì¤¬¥¢¥ó¥À¡¼¥Õ¥í¡¼¤òµ¯¤³¤·¤¿¾ì¹ç¤Ë¤Ï 0 ¤¬Ê֤ꡢ
.B ERANGE
¤¬
.I errno
¤ËÂåÆþ¤µ¤ì¤ë¡£
.\"O .SH ERRORS
.SH ¥¨¥é¡¼
.TP
.B ERANGE
.\"O Overflow or underflow occurred.
¥ª¡¼¥Ð¡¼¥Õ¥í¡¼¤Þ¤¿¤Ï¥¢¥ó¥À¡¼¥Õ¥í¡¼¤¬µ¯¤³¤Ã¤¿¡£
.\"O .SH "CONFORMING TO"
.SH ½àµò
.\"O C89 describes
.\"O .BR strtod (),
.\"O C99
.\"O describes the other two functions.
C89 ¤Ç¤Ï
.BR strtod ()
¤¬¡¢C99 ¤Ç¤Ï»Ä¤ê¤Î 2 ¤Ä¤Î´Ø¿ô¤¬µ­½Ò¤µ¤ì¤Æ¤¤¤ë¡£
.\"O .SH NOTES
.SH Ãí°Õ
.\"O Since
.\"O 0 can legitimately be returned
.\"O on both success and failure, the calling program should set
.\"O .I errno
.\"O to 0 before the call,
.\"O and then determine if an error occurred by checking whether
.\"O .I errno
.\"O has a nonzero value after the call.
À®¸ù¡¢¼ºÇԤɤÁ¤é¤Î¾ì¹ç¤Ç¤â 0 ¤òÊÖ¤¹²ÄǽÀ­¤¬¤¢¤ë¤Î¤Ç¡¢
¥×¥í¥°¥é¥à¤Ï¸Æ¤Ó½Ð¤¹Á°¤Ë
.I errno
¤ò 0 ¤ËÀßÄꤷ¡¢¸Æ¤Ó½Ð¤·¸å¤Ë
.I errno
¤¬ 0 °Ê³°¤ÎÃͤ«¤É¤¦¤«¤ò³Îǧ¤·¥¨¥é¡¼¤¬È¯À¸¤·¤¿¤«¤É¤¦¤«¤òȽÃǤ¹¤ë
ɬÍפ¬¤¢¤ë¡£
.\"O .SH EXAMPLE
.SH Îã
.\"O See the example on the
.\"O .BR strtol (3)
.\"O manual page;
.\"O the use of the functions described in this manual page is similar.
.BR strtol (3)
¤Î¥Þ¥Ë¥å¥¢¥ë¥Ú¡¼¥¸¤ÎÎã¤ò»²¾È¡£
¤³¤Î¥Ú¡¼¥¸¤ÇÀâÌÀ¤·¤¿´Ø¿ô¤Î»ÈÍÑÊýË¡¤âƱÍͤǤ¢¤ë¡£
.\"O .SH "SEE ALSO"
.SH ´ØÏ¢¹àÌÜ
.BR atof (3),
.BR atoi (3),
.BR atol (3),
.BR strtol (3),
.BR strtoul (3)