(split) LDP v3.24 -> v3.29 の定型的な変更内容を反映。

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

.\" Hey Emacs! This file is -*- nroff -*- source.
.\"
.\" Copyright (C) 2006 Michael Kerrisk <mtk.manpages@gmail.com>
.\" A few fragments remain from an earlier (1992) page by
.\" Drew Eckhardt (drew@cs.colorado.edu),
.\"
.\" 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.\" manual page may be incorrect or out-of-date.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.
.\"
.\" Modified by Michael Haardt (michael@moria.de)
.\" Modified Sat Jul 24 13:22:07 1993 by Rik Faith (faith@cs.unc.edu)
.\" Modified 21 Aug 1994 by Michael Chastain (mec@shell.portal.com):
.\"   Referenced 'clone(2)'.
.\" Modified 1995-06-10, 1996-04-18, 1999-11-01, 2000-12-24
.\"   by Andries Brouwer (aeb@cwi.nl)
.\" Modified, 27 May 2004, Michael Kerrisk <mtk.manpages@gmail.com>
.\"     Added notes on capability requirements
.\" 2006-09-04, Michael Kerrisk
.\"     Greatly expanded, to describe all attributes that differ
.\"     parent and child.
.\"
.\" Japanese Version Copyright (c) 1996 TABATA Tomohira
.\"         all rights reserved.
.\" Translated Thu Jun 27 20:35:06 JST 1996
.\"         by TABATA Tomohira <loba@k2.t.u-tokyo.ac.jp>
.\" Modified Sun Dec 14 00:43:22 JST 1997
.\"         by HANATAKA Shinya <hanataka@abyss.rim.or.jp>
.\" Modified Tue Jul 10 05:36:22 JST 2001
.\"         by Yuichi SATO <ysato@h4.dion.ne.jp>, LDP v1.38
.\" Updated & Modified Wed Dec 29 12:33:12 JST 2004
.\"         by Yuichi SATO <ysato444@yahoo.co.jp>, LDP v2.01
.\" Updated & Modified Wed Jan  3 04:11:03 JST 2007 by Yuichi SATO, LDP v2.43
.\" Updated 2008-08-04, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>, LDP v3.05
.\"
.TH FORK 2 2009-04-27 "Linux" "Linux Programmer's Manual"
.\"O .SH NAME
.SH ̾Á°
.\"O fork \- create a child process
fork \- »Ò¥×¥í¥»¥¹¤òÀ¸À®¤¹¤ë
.\"O .SH SYNOPSIS
.SH ½ñ¼°
.B #include <unistd.h>
.sp
.B pid_t fork(void);
.\"O .SH DESCRIPTION
.SH ÀâÌÀ
.\"O .BR fork ()
.\"O creates a new process by duplicating the calling process.
.\"O The new process, referred to as the \fIchild\fP,
.\"O is an exact duplicate of the calling process,
.\"O referred to as the \fIparent\fP, except for the following points:
.BR fork ()
¤Ï¸Æ¤Ó½Ð¤·¸µ¥×¥í¥»¥¹¤òÊ£À½¤·¤Æ¿·¤·¤¤¥×¥í¥»¥¹¤òÀ¸À®¤¹¤ë¡£
\fIchild\fP ¤Ç»²¾È¤µ¤ì¤ë¿·¤·¤¤¥×¥í¥»¥¹¤Ï¡¢°Ê²¼¤ÎÅÀ¤ò½ü¤­¡¢
\fIparent\fP ¤Ç»²¾È¤µ¤ì¤ë¸Æ¤Ó½Ð¤·¸µ¥×¥í¥»¥¹¤Î´°Á´¤ÊÊ£À½¤Ç¤¢¤ë:
.IP * 3
.\"O The child has its own unique process ID,
.\"O and this PID does not match the ID of any existing process group
.\"O .RB ( setpgid (2)).
»Ò¥×¥í¥»¥¹¤ÏÆȼ«¤Î¥×¥í¥»¥¹ ID ¤ò»ý¤Á¡¢
¤³¤Î PID ¤Ï´û¸¤Î¤É¤Î¥×¥í¥»¥¹¥°¥ë¡¼¥×
.RB ( setpgid (2))
¤Î ID ¤È¤â°ìÃפ·¤Ê¤¤¡£
.IP *
.\"O The child's parent process ID is the same as the parent's process ID.
»Ò¥×¥í¥»¥¹¤Î¿Æ¥×¥í¥»¥¹ ID ¤Ï¡¢¿Æ¥×¥í¥»¥¹¤Î¥×¥í¥»¥¹ ID ¤ÈƱ¤¸¤Ç¤¢¤ë¡£
.IP *
.\"O The child does not inherit its parent's memory locks
.\"O .RB ( mlock (2),
.\"O .BR mlockall (2)).
»Ò¥×¥í¥»¥¹¤Ï¿Æ¥×¥í¥»¥¹¤Î¥á¥â¥ê¥í¥Ã¥¯
.RB ( mlock (2),
.BR mlockall (2))
¤ò°ú¤­·Ñ¤¬¤Ê¤¤¡£
.IP *
.\"O Process resource utilizations
.\"O .RB ( getrusage (2))
.\"O and CPU time counters
.\"O .RB ( times (2))
.\"O are reset to zero in the child.
¥×¥í¥»¥¹¤Î»ñ¸»ÍøÍÑÎÌ
.RB ( getrusage (2))
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.RB ( times (2))
¤¬¡¢»Ò¥×¥í¥»¥¹¤Ç¤Ï 0 ¤Ë¥ê¥»¥Ã¥È¤µ¤ì¤ë¡£
.IP *
.\"O The child's set of pending signals is initially empty
.\"O .RB ( sigpending (2)).
»Ò¥×¥í¥»¥¹¤Î½èÍýÂÔ¤Á¤Î¥·¥°¥Ê¥ë¤Î½¸¹ç
.RB ( sigpending (2))
¤Ï¡¢½é´ü¾õÂ֤Ǥ϶õ¤Ë¤Ê¤ë¡£
.IP *
.\"O The child does not inherit semaphore adjustments from its parent
.\"O .RB ( semop (2)).
»Ò¥×¥í¥»¥¹¤Ï¿Æ¥×¥í¥»¥¹¤«¤é¥»¥Þ¥Õ¥©Ä´À°
.RB ( semop (2))
¤ò°ú¤­·Ñ¤¬¤Ê¤¤¡£
.IP *
.\"O The child does not inherit record locks from its parent
.\"O .RB ( fcntl (2)).
»Ò¥×¥í¥»¥¹¤Ï¿Æ¥×¥í¥»¥¹¤«¤é¥ì¥³¡¼¥É¥í¥Ã¥¯
.RB ( fcntl (2))
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.IP *
.\"O The child does not inherit timers from its parent
.\"O .RB ( setitimer (2),
.\"O .BR alarm (2),
.\"O .BR timer_create (2)).
»Ò¥×¥í¥»¥¹¤Ï¿Æ¥×¥í¥»¥¹¤«¤é¥¿¥¤¥Þ¡¼
.RB ( setitimer (2),
.BR alarm (2),
.BR timer_create (2))
¤ò°ú¤­·Ñ¤¬¤Ê¤¤¡£
.IP *
.\"O The child does not inherit outstanding asynchronous I/O operations
.\"O from its parent
.\"O .RB ( aio_read (3),
.\"O .BR aio_write (3)),
.\"O nor does it inherit any asynchronous I/O contexts from its parent (see
.\"O .BR io_setup (2)).
»Ò¥×¥í¥»¥¹¤Ï¿Æ¥×¥í¥»¥¹¤«¤é¼ç¤À¤Ã¤¿ÈóƱ´ü I/O Áàºî¤ò°ú¤­·Ñ¤¬¤Ê¤¤
.RB ( aio_read (3),
.BR aio_write (3)
»²¾È)¡£
¤Þ¤¿¡¢¿Æ¥×¥í¥»¥¹¤«¤éÈóƱ´ü I/O ¥³¥ó¥Æ¥­¥¹¥È¤ò°ú¤­·Ñ¤¬¤Ê¤¤
.RB ( io_setup (2)
»²¾È)¡£
.PP
.\"O The process attributes in the preceding list are all specified
.\"O in POSIX.1-2001.
.\"O The parent and child also differ with respect to the following
.\"O Linux-specific process attributes:
¾åµ­¤Î¥ê¥¹¥È¤Ë¤¢¤ë¥×¥í¥»¥¹Â°À­¤Ï¡¢POSIX.1-2001 ¤ÇÁ´¤Æ»ØÄꤵ¤ì¤Æ¤¤¤ë¡£
¿Æ¥×¥í¥»¥¹¤È»Ò¥×¥í¥»¥¹¤Ï¡¢°Ê²¼¤Î Linux ¸ÇÍ­¤Î¥×¥í¥»¥¹Â°À­¤â°Û¤Ê¤ë:
.IP * 3
.\"O The child does not inherit directory change notifications (dnotify)
.\"O from its parent
.\"O (see the description of
.\"O .B F_NOTIFY
.\"O in
.\"O .BR fcntl (2)).
»Ò¥×¥í¥»¥¹¤Ï¿Æ¥×¥í¥»¥¹¤«¤é¥Ç¥£¥ì¥¯¥È¥êÊѹ¹ÄÌÃÎ (dnotify)
.RB ( fcntl (2)
¤Ë¤ª¤±¤ë
.B F_NOTIFY
¤ÎÀâÌÀ¤ò»²¾È) ¤ò°ú¤­·Ñ¤¬¤Ê¤¤¡£
.IP *
.\"O The
.\"O .BR prctl (2)
.\"O .B PR_SET_PDEATHSIG
.\"O setting is reset so that the child does not receive a signal
.\"O when its parent terminates.
.BR prctl (2)
¤Î
.B PR_SET_PDEATHSIG
¤ÎÀßÄ꤬¥ê¥»¥Ã¥È¤µ¤ì¡¢»Ò¥×¥í¥»¥¹¤Ï¿Æ¥×¥í¥»¥¹¤¬½ªÎ»¤·¤¿¤È¤­¤Ë
¥·¥°¥Ê¥ë¤ò¼õ¿®¤·¤Ê¤¤¡£
.IP *
.\"O Memory mappings that have been marked with the
.\"O .BR madvise (2)
.\"O .B MADV_DONTFORK
.\"O flag are not inherited across a
.\"O .BR fork ().
.BR madvise (2)
¤Î
.B MADV_DONTFORK
¥Õ¥é¥°¤Ç¥Þ¡¼¥¯¤µ¤ì¤¿¥á¥â¥ê¥Þ¥Ã¥Ô¥ó¥°¤Ï¡¢
.BR fork ()
¤Ë¤è¤Ã¤Æ°ú¤­·Ñ¤¬¤ì¤Ê¤¤¡£
.IP *
.\"O The termination signal of the child is always
.\"O .B SIGCHLD
.\"O (see
.\"O .BR clone (2)).
»Ò¥×¥í¥»¥¹¤Î½ªÎ»¥·¥°¥Ê¥ë¤Ï¾ï¤Ë
.B SIGCHLD
¤Ç¤¢¤ë
.RB ( clone (2)
¤ò»²¾È)¡£
.PP
.\"O Note the following further points:
¤µ¤é¤Ë°Ê²¼¤ÎÅÀ¤Ë¤Ä¤¤¤ÆÃí°Õ¤¹¤ë¤³¤È:
.IP * 3
.\"O The child process is created with a single thread \(em the
.\"O one that called
.\"O .BR fork ().
»Ò¥×¥í¥»¥¹¤Ï¥·¥ó¥°¥ë¥¹¥ì¥Ã¥É¤ÇÀ¸À®¤µ¤ì¤ë¡£¤Ä¤Þ¤ê¡¢
.BR fork ()
¤ò¸Æ¤Ó½Ð¤·¤¿¥¹¥ì¥Ã¥É¤È¤Ê¤ë¡£
.\"O The entire virtual address space of the parent is replicated in the child,
.\"O including the states of mutexes, condition variables,
.\"O and other pthreads objects; the use of
.\"O .BR pthread_atfork (3)
.\"O may be helpful for dealing with problems that this can cause.
¿Æ¥×¥í¥»¥¹¤Î²¾ÁÛ¥¢¥É¥ì¥¹¶õ´ÖÁ´ÂΤ¬»Ò¥×¥í¥»¥¹¤ËÊ£À½¤µ¤ì¤ë¡£
¤³¤ì¤Ë¤Ï¥ß¥å¡¼¥Æ¥Ã¥¯¥¹ (mutex) ¤Î¾õÂÖ¡¦¾ò·ïÊÑ¿ô¡¦
pthread ¥ª¥Ö¥¸¥§¥¯¥È¤¬´Þ¤Þ¤ì¤ë¡£
¤³¤ì¤¬°ú¤­µ¯¤³¤¹ÌäÂê¤ò°·¤¦¤Ë¤Ï¡¢
.BR pthread_atfork (3)
¤ò»È¤¦¤ÈÎɤ¤¤À¤í¤¦¡£
.IP *
.\"O The child inherits copies of the parent's set of open file descriptors.
.\"O Each file descriptor in the child refers to the same
.\"O open file description (see
.\"O .BR open (2))
.\"O as the corresponding file descriptor in the parent.
»Ò¥×¥í¥»¥¹¤Ï¿Æ¥×¥í¥»¥¹¤¬»ý¤Ä
¥ª¡¼¥×¥ó¥Õ¥¡¥¤¥ë¥Ç¥£¥¹¥¯¥ê¥×¥¿¤Î½¸¹ç¤Î¥³¥Ô¡¼¤ò°ú¤­·Ñ¤°¡£
»Ò¥×¥í¥»¥¹¤Î³Æ¥Õ¥¡¥¤¥ë¥Ç¥£¥¹¥¯¥ê¥×¥¿¤Ï¡¢
¿Æ¥×¥í¥»¥¹¤Î¥Õ¥¡¥¤¥ë¥Ç¥£¥¹¥¯¥ê¥×¥¿¤ËÂбþ¤¹¤ë
Ʊ¤¸¥ª¡¼¥×¥ó¥Õ¥¡¥¤¥ëµ­½Ò (file description) ¤ò»²¾È¤¹¤ë
.RB ( open (2)
¤ò»²¾È)¡£
.\"O This means that the two descriptors share open file status flags,
.\"O current file offset,
.\"O and signal-driven I/O attributes (see the description of
.\"O .B F_SETOWN
.\"O and
.\"O .B F_SETSIG
.\"O in
.\"O .BR fcntl (2)).
¤³¤ì¤Ï 2 ¤Ä¤Î¥Ç¥£¥¹¥¯¥ê¥×¥¿¤¬¡¢¥Õ¥¡¥¤¥ë¾õÂ֥ե饰¡¦
¸½ºß¤Î¥Õ¥¡¥¤¥ë¥ª¥Õ¥»¥Ã¥È¡¢¥·¥°¥Ê¥ë¶îÆ° (signal-driven) I/O °À­
.RB ( fcntl (2)
¤Ë¤ª¤±¤ë
.BR F_SETOWN ,
.B F_SETSIG
¤ÎÀâÌÀ¤ò»²¾È) ¤ò¶¦Í­¤¹¤ë¤³¤È¤ò°ÕÌ£¤¹¤ë¡£
.IP *
.\"O The child inherits copies of the parent's set of open message
.\"O queue descriptors (see
.\"O .BR mq_overview (7)).
»Ò¥×¥í¥»¥¹¤Ï¿Æ¥×¥í¥»¥¹¤¬»ý¤Ä¥ª¡¼¥×¥ó¥á¥Ã¥»¡¼¥¸¥­¥å¡¼¥Ç¥£¥¹¥¯¥ê¥×¥¿
.RB ( mq_overview (7)
¤ò»²¾È) ¤Î½¸¹ç¤Î¥³¥Ô¡¼¤ò°ú¤­·Ñ¤°¡£
.\"O Each descriptor in the child refers to the same
.\"O open message queue description
.\"O as the corresponding descriptor in the parent.
»Ò¥×¥í¥»¥¹¤Î³Æ¥Ç¥£¥¹¥¯¥ê¥×¥¿¤Ï¡¢
¿Æ¥×¥í¥»¥¹¤Î¥Ç¥£¥¹¥¯¥ê¥×¥¿¤ËÂбþ¤¹¤ë
Ʊ¤¸¥ª¡¼¥×¥ó¥á¥Ã¥»¡¼¥¸¥­¥å¡¼¥Ç¥£¥¹¥¯¥ê¥×¥¿¤ò»²¾È¤¹¤ë¡£
.\"O This means that the two descriptors share the same flags
.\"O .RI ( mq_flags ).
¤³¤ì¤Ï 2 ¤Ä¤Î¥Ç¥£¥¹¥¯¥ê¥×¥¿¤¬Æ±¤¸¥Õ¥é¥°
.RI ( mq_flags )
¤ò¶¦Í­¤¹¤ë¤³¤È¤ò°ÕÌ£¤¹¤ë¡£
.IP *
.\"O The child inherits copies of the parent's set of open directory streams (see
.\"O .BR opendir (3)).
.\"O POSIX.1-2001 says that the corresponding directory streams
.\"O in the parent and child
.\"O .I may
.\"O share the directory stream positioning;
.\"O on Linux/glibc they do not.
»Ò¥×¥í¥»¥¹¤Ï¡¢¿Æ¥×¥í¥»¥¹¤Î¥ª¡¼¥×¥óºÑ¤ß¤Î¥Ç¥£¥ì¥¯¥È¥ê¥¹¥È¥ê¡¼¥à¤Î½¸¹ç
.RB ( opendir (3)
»²¾È) ¤Î¥³¥Ô¡¼¤ò·Ñ¾µ¤¹¤ë¡£
POSIX.1-2001 ¤Ç¤Ï¡¢¿Æ¥×¥í¥»¥¹¤È»Ò¥×¥í¥»¥¹´Ö¤ÎÂбþ¤¹¤ë¥Ç¥£¥ì¥¯¥È¥ê¥¹¥È¥ê¡¼¥à
¤Ï¥Ç¥£¥ì¥¯¥È¥ê¥¹¥È¥ê¡¼¥à¤Î°ÌÃÖ (positioning) ¤ò¶¦Í­¤·¤Æ¤â¤è¤¤¤È¤µ¤ì¤Æ¤¤¤ë¡£
Linux/glibc ¤Ç¤Ï¥Ç¥£¥ì¥¯¥È¥ê¥¹¥È¥ê¡¼¥à¤Î°ÌÃ֤ζ¦Í­¤Ï¹Ô¤ï¤ì¤Æ¤¤¤Ê¤¤¡£
.\"O .SH "RETURN VALUE"
.SH ÊÖ¤êÃÍ
.\"O On success, the PID of the child process is returned in the parent,
.\"O and 0 is returned in the child.
.\"O On failure, \-1 is returned in the parent,
.\"O no child process is created, and
.\"O .I errno
.\"O is set appropriately.
À®¸ù¤·¤¿¾ì¹ç¡¢¿Æ¥×¥í¥»¥¹¤Ë¤Ï»Ò¥×¥í¥»¥¹¤Î PID ¤¬ÊÖ¤µ¤ì¡¢
»Ò¥×¥í¥»¥¹¤Ë¤Ï 0 ¤¬ÊÖ¤µ¤ì¤ë¡£
¼ºÇÔ¤·¤¿¾ì¹ç¡¢¿Æ¥×¥í¥»¥¹¤Ë \-1 ¤¬ÊÖ¤µ¤ì¡¢»Ò¥×¥í¥»¥¹¤ÏÀ¸À®¤µ¤ì¤º¡¢
.I errno
¤¬Å¬ÀÚ¤ËÀßÄꤵ¤ì¤ë¡£
.\"O .SH ERRORS
.SH ¥¨¥é¡¼
.TP
.B EAGAIN
.\"O .BR fork ()
.\"O cannot allocate sufficient memory to copy the parent's page tables and
.\"O allocate a task structure for the child.
¿Æ¥×¥í¥»¥¹¤Î¥Ú¡¼¥¸¡¦¥Æ¡¼¥Ö¥ë¤Î¥³¥Ô¡¼¤È
»Ò¥×¥í¥»¥¹¤Î¥¿¥¹¥¯¹½Â¤¤ËÀ¸À®¤ËɬÍפʥá¥â¥ê¤ò
.BR fork ()
¤¬³ä¤êÅö¤Æ¤ë¤³¤È¤¬¤Ç¤­¤Ê¤«¤Ã¤¿¡£
.TP
.B EAGAIN
.\"O It was not possible to create a new process because the caller's
.\"O .B RLIMIT_NPROC
.\"O resource limit was encountered.
¸Æ¤Ó½Ð¤·¸µ¤Î
.B RLIMIT_NPROC
»ñ¸»¤ÎÀ©¸Â (resource limit) ¤Ë㤷¤¿¤¿¤á¤Ë¡¢¿·¤·¤¤¥×¥í¥»¥¹¤òÀ¸À®¤Ç¤­¤Ê¤«¤Ã¤¿¡£
.\"O To exceed this limit, the process must have either the
.\"O .B CAP_SYS_ADMIN
.\"O or the
.\"O .B CAP_SYS_RESOURCE
.\"O capability.
¤³¤ÎÀ©¸Â¤òĶ¤¨¤ë¤Ë¤Ï¡¢¥×¥í¥»¥¹¤Ï
.B CAP_SYS_ADMIN
¤Þ¤¿¤Ï
.B CAP_SYS_RESOURCE
¥±¡¼¥Ñ¥Ó¥ê¥Æ¥£ (capability) ¤ò»ý¤Ã¤Æ¤¤¤Ê¤¯¤Æ¤Ï¤Ê¤é¤Ê¤¤¡£
.TP
.B ENOMEM
.\"O .BR fork ()
.\"O failed to allocate the necessary kernel structures because memory is tight.
¥á¥â¥ê¤¬Â­¤ê¤Ê¤¤¤¿¤á¤Ë¡¢
.BR fork ()
¤ÏɬÍפʥ«¡¼¥Í¥ë¹½Â¤ÂΤò³ä¤êÅö¤Æ¤ë¤³¤È¤¬¤Ç¤­¤Ê¤«¤Ã¤¿¡£
.\"O .SH "CONFORMING TO"
.SH ½àµò
SVr4, 4.3BSD, POSIX.1-2001.
.\"O .SH NOTES
.SH Ãí°Õ
.\"O .PP
.\"O Under Linux,
.\"O .BR fork ()
.\"O is implemented using copy-on-write pages, so the only penalty that it incurs
.\"O is the time and memory required to duplicate the parent's page tables,
.\"O and to create a unique task structure for the child.
Linux ¤Ç¤Ï¡¢
.BR fork ()
¤ò ½ñ¤­¹þ¤ß»þ¥³¥Ô¡¼ (copy-on-write)¡¦¥Ú¡¼¥¸¤òÍѤ¤¤Æ¼ÂÁõ¤·¤Æ¤¤¤ë¡£
¤·¤¿¤¬¤Ã¤Æ¡¢fork ¤ò¹Ô¤¦¤³¤È¤ÎÍ£°ì¤Î¥Ç¥á¥ê¥Ã¥È¤Ï¡¢
¿Æ¥×¥í¥»¥¹¤Î¥Ú¡¼¥¸¡¦¥Æ¡¼¥Ö¥ë¤òÊ£À½¤È
»Ò¥×¥í¥»¥¹¼«¿È¤Î¥¿¥¹¥¯¹½Â¤¤ÎºîÀ®¤Î¤¿¤á¤Î»þ´Ö¤È¥á¥â¥ê¤¬É¬Íפʤ³¤È¤Ç¤¢¤ë¡£

.\"O Since version 2.3.3,
.\"O .\" nptl/sysdeps/unix/sysv/linux/fork.c
.\"O rather than invoking the kernel's
.\"O .BR fork ()
.\"O system call,
.\"O the glibc
.\"O .BR fork ()
.\"O wrapper that is provided as part of the
.\"O NPTL threading implementation invokes
.\"O .BR clone (2)
.\"O with flags that provide the same effect as the traditional system call.
.\"O The glibc wrapper invokes any fork handlers that have been
.\"O established using
.\"O .BR pthread_atfork (3).
.\"O .\" and does some magic to ensure that getpid(2) returns the right value.
glibc 2.3.3 °Ê¹ß¤Ç¤Ï¡¢
NPTL ¥¹¥ì¥Ã¥É¼ÂÁõ¤Î°ìÉô¤È¤·¤ÆÄ󶡤µ¤ì¤Æ¤¤¤ë glibc ¤Î
.BR fork ()
¥é¥Ã¥Ñ¡¼´Ø¿ô¤Ï¡¢
¥«¡¼¥Í¥ë¤Î
.BR fork ()
¥·¥¹¥Æ¥à¥³¡¼¥ë¤òµ¯Æ°¤¹¤ë¤Î¤Ç¤Ï¤Ê¤¯¡¢
.BR clone (2)
¤òµ¯Æ°¤¹¤ë¡£
.BR clone (2)
¤ËÅϤ¹¥Õ¥é¥°¤È¤·¤Æ¡¢ÅÁÅýŪ¤Ê
.BR fork ()
¥·¥¹¥Æ¥à¥³¡¼¥ë¤ÈƱ¤¸¸ú²Ì¤¬ÆÀ¤é¤ì¤ë¤è¤¦¤Ê¥Õ¥é¥°¤¬»ØÄꤵ¤ì¤ë¡£
glibc ¤Î¥é¥Ã¥Ñ¡¼´Ø¿ô¤Ï
.BR pthread_atfork (3)
¤ò»È¤Ã¤ÆÀßÄꤵ¤ì¤Æ¤¤¤ëǤ°Õ¤Î fork ¥Ï¥ó¥É¥é¤òµ¯Æ°¤¹¤ë¡£
.\" getpid(2) ¤¬Àµ¤·¤¤ÃͤòÊÖ¤¹¤³¤È¤¬¤Ç¤­¤ë¤è¤¦¤Ë²¿¤é¤«¤Î½èÍý¤ò¹Ô¤¦¡£

.\"O .SH EXAMPLE
.SH Îã
.\"O See
.\"O .BR pipe (2)
.\"O and
.\"O .BR wait (2).
.BR pipe (2)
¤ª¤è¤Ó
.BR wait (2)
¤ò»²¾È¡£
.\"O .SH "SEE ALSO"
.SH ´ØÏ¢¹àÌÜ
.BR clone (2),
.BR execve (2),
.BR setrlimit (2),
.BR unshare (2),
.BR vfork (2),
.BR wait (2),
.BR daemon (3),
.BR capabilities (7),
.BR credentials (7)