[linuxjm/LDP_man-pages.git] / draft / man2 / getpagesize.2

.\" Copyright (C) 2001 Andries Brouwer <aeb@cwi.nl>
.\"
.\" 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.\" manual page may be incorrect or out-of-date.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) 1997 HANATAKA Shinya
.\"         all rights reserved.
.\" Translated 2002-04-14, HANATAKA Shinya <hanataka@abyss.rim.or.jp>
.\" Updated 2003-07-03, Akihiro Motoki <amotoki@dd.iij4u.or.jp>
.\" Updated 2007-01-07, Akihiro MOTOKI, catch up to LDP v2.43
.\"
.\"WORD:        page                    ¥Ú¡¼¥¸
.\"WORD:        legacy                  ²áµî¤Î°äʪ
.\"
.TH GETPAGESIZE 2 2007-07-26 "Linux" "Linux Programmer's Manual"
.\"O .SH NAME
.SH ̾Á°
.\"O getpagesize \- get memory page size
getpagesize \- ¥á¥â¥ê¤Î¥Ú¡¼¥¸¡¦¥µ¥¤¥º¤ò¼èÆÀ¤¹¤ë
.SH ½ñ¼°
.B #include <unistd.h>
.sp
.B int getpagesize(void);
.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
.sp
.BR getpagesize ():
_BSD_SOURCE || _XOPEN_SOURCE\ >=\ 500
.\"O .SH DESCRIPTION
.SH ÀâÌÀ
.\"O The function
.\"O .BR getpagesize ()
.\"O returns the number of bytes in a page, where a "page" is the thing
.\"O used where it says in the description of
.\"O .BR mmap (2)
.\"O that files are mapped in page-sized units.
.BR getpagesize ()
´Ø¿ô¤Ï¥Ú¡¼¥¸¤ÎÂ礭¤µ¤ò¥Ð¥¤¥È¿ô¤ÇÊÖ¤¹¡£¤³¤³¤Ç¤Î¡Ö¥Ú¡¼¥¸¡×¤Ï
.BR mmap (2)
¤ÎÀâÌÀ¤ÎÃæ¤Ç»ÈÍѤµ¤ì¤Æ¤¤¤ë¤â¤Î¤Ç¡¢
.BR mmap ()
¤Ï¤³¤Î¥Ú¡¼¥¸¥µ¥¤¥º¤Îñ°Ì¤Ç¥Õ¥¡¥¤¥ë¤ò¥Þ¥Ã¥×¤¹¤ë¡£

.\"O The size of the kind of pages that
.\"O .BR mmap (2)
.\"O uses, is found using
.BR mmap (2)
¤¬»ÈÍѤ¹¤ë¥Ú¡¼¥¸¥µ¥¤¥º¤Ï°Ê²¼¤Î¤è¤¦¤Ë¤·¤ÆÃΤ뤳¤È¤¬¤Ç¤­¤ë¡£

.in +4n
.nf
#include <unistd.h>
long sz = sysconf(_SC_PAGESIZE);
.fi
.in

.\"O (most systems allow the synonym
.\"O .B _SC_PAGE_SIZE
.\"O for
.\"O .BR _SC_PAGESIZE ),
.\"O or
(¤Û¤È¤ó¤É¤Î¥·¥¹¥Æ¥à¤Ç¤Ï
.B _SC_PAGESIZE
¤ÎƱµÁ¸ì¤È¤·¤Æ
.B _SC_PAGE_SIZE
¤ò»ÈÍѤ¹¤ë¤³¤È¤¬¤Ç¤­¤ë)¡¢¤â¤·¤¯¤Ï°Ê²¼¤Î¤è¤¦¤Ë¤¹¤ë:

.in +4n
.nf
#include <unistd.h>
int sz = getpagesize();
.fi
.in
.\"O .\" .SH HISTORY
.\" .SH Îò»Ë
.\"O .\" This call first appeared in 4.2BSD.
.\" ¤³¤Î¥·¥¹¥Æ¥à¥³¡¼¥ë¤Ï 4.2BSD ¤Ç½é¤á¤ÆÅо줷¤¿¡£
.\"O .SH CONFORMING TO
.SH ½àµò
SVr4, 4.4BSD, SUSv2.
.\"O In SUSv2 the
.\"O .BR getpagesize ()
.\"O call is labeled LEGACY, and in POSIX.1-2001
.\"O it has been dropped;
.\"O HP-UX does not have this call.
.\"O Portable applications should employ
.\"O .I sysconf(_SC_PAGESIZE)
.\"O instead of this call.
SUSv2 ¤Ç¤Ï
.BR getpagesize ()
¥·¥¹¥Æ¥à¥³¡¼¥ë¤Ï¡Ö²áµî¤Î°äʪ (LEGACY)¡×¤È¤µ¤ì¤Æ¤ª¤ê¡¢
POSIX.1-2001 ¤«¤é¤Ï³°¤µ¤ì¤Æ¤¤¤ë¡£
HP-UX ¤Ë¤Ï¤³¤Î¥·¥¹¥Æ¥à¥³¡¼¥ë¤Ï¸ºß¤·¤Ê¤¤¡£
°Ü¿¢À­¤¬É¬Íפʥ¢¥×¥ê¥±¡¼¥·¥ç¥ó¤Ç¤Ï¡¢¤³¤Î¥·¥¹¥Æ¥à¥³¡¼¥ë¤ÎÂå¤ï¤ê¤Ë
.I sysconf(_SC_PAGESIZE)
¤òÍøÍѤ¹¤Ù¤­¤Ç¤¢¤ë¡£
.\"O .SH NOTES
.SH Ãí°Õ
.\"O Whether
.\"O .BR getpagesize ()
.\"O is present as a Linux system call depends on the architecture.
.BR getpagesize ()
¤¬ Linux ¤Î¥·¥¹¥Æ¥à¥³¡¼¥ë¤È¤·¤Æ¸ºß¤¹¤ë¤«¤É¤¦¤«¤Ï¡¢¤½¤Î¥¢¡¼¥­¥Æ¥¯¥Á¥ã¤Ë
°Í¸¤·¤Æ¤¤¤ë¡£
.\"O If it is, it returns the kernel symbol
.\"O .BR PAGE_SIZE ,
.\"O whose value depends on the architecture and machine model.
¥·¥¹¥Æ¥à¥³¡¼¥ë¤È¤·¤Æ¸ºß¤¹¤ë¾ì¹ç¤Ë¤Ï¡¢¥«¡¼¥Í¥ë¥·¥ó¥Ü¥ë¤Î
.B PAGE_SIZE
¤òÊÖ¤¹¡£
.B PAGE_SIZE
¤ÎÃͤϡ¢¥¢¡¼¥­¥Æ¥¯¥Á¥ã¤È¥Þ¥·¥ó¥â¥Ç¥ë¤Ë°Í¸¤¹¤ë¡£
.\"O Generally, one uses binaries that are dependent on the architecture but not
.\"O on the machine model, in order to have a single binary
.\"O distribution per architecture.
.\"O This means that a user program
.\"O should not find
.\"O .B PAGE_SIZE
.\"O at compile time from a header file,
.\"O but use an actual system call, at least for those architectures
.\"O (like sun4) where this dependency exists.
°ìÈ̤ˡ¢¥Ð¥¤¥Ê¥ê¤Ï¡¢¥¢¡¼¥­¥Æ¥¯¥Á¥ã¤´¤È¤Ë1¤Ä¤Î¥Ð¥¤¥Ê¥êÇÛÉۤǺѤޤ»¤ë¤¿¤á¤Ë¡¢
¥¢¡¼¥­¥Æ¥¯¥Á¥ã¤Ë¤Ï°Í¸¤·¤Æ¤¤¤ë¤¬¥Þ¥·¥ó¥â¥Ç¥ë¤Ë¤Ï°Í¸¤·¤Æ¤¤¤Ê¤¤¡£
¤Ä¤Þ¤ê¡¢¥æ¡¼¥¶¥×¥í¥°¥é¥à¤Ï¥³¥ó¥Ñ¥¤¥ë»þ¤Ë¥Ø¥Ã¥À¡¼¥Õ¥¡¥¤¥ë¤«¤é
.B PAGE_SIZE
¤ò¸«¤Ä¤±¤Æ»ÈÍѤ¹¤Ù¤­¤Ç¤Ï¤Ê¤¤¡£
¾¯¤Ê¤¯¤È¤â¡¢¥Þ¥·¥ó¥â¥Ç¥ë¤Ë¤Ä¤¤¤Æ¤â°Í¸À­¤¬Â¸ºß¤¹¤ë (sun4 ¤Î¤è¤¦¤Ê)
¥¢¡¼¥­¥Æ¥¯¥Á¥ã¤Ë¤ª¤¤¤Æ¤ÏËÜʪ¤Î¥·¥¹¥Æ¥à¥³¡¼¥ë¤ò»ÈÍѤ¹¤ëɬÍפ¬¤¢¤ë¡£
.\"O Here libc4, libc5, glibc 2.0 fail because their
.\"O .BR getpagesize ()
.\"O returns a statically derived value, and does not use a system call.
.\"O Things are OK in glibc 2.1.
¾°¡¢ libc4, libc5, glibc 2.0 ¤Ç¤Ï¡¢
.BR getpagesize ()
¤¬¥·¥¹¥Æ¥à¡¦¥³¡¼¥ë¤ò»ÈÍѤ»¤º¡¢¸ÇÄê¤ÎÃͤòÊÖ¤¹¤¿¤á¤Ë¡¢¤³¤ÎÊýË¡¤Ï
¼ºÇÔ¤¹¤ë¡£glibc 2.1 ¤Ç¤ÏÂç¾æÉפǤ¢¤ë¡£
.\"O .SH "SEE ALSO"
.SH ´ØÏ¢¹àÌÜ
.BR mmap (2),
.BR sysconf (3)