mirror of https://github.com/mkerrisk/man-pages
99 lines
2.7 KiB
Groff
99 lines
2.7 KiB
Groff
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.\" Hey Emacs! This file is -*- nroff -*- source.
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.\"
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.\" Copyright (C) Markus Kuhn, 1996
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.\"
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.\" This is free documentation; you can redistribute it and/or
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.\" modify it under the terms of the GNU General Public License as
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.\" published by the Free Software Foundation; either version 2 of
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.\" the License, or (at your option) any later version.
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.\"
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.\" The GNU General Public License's references to "object code"
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.\" and "executables" are to be interpreted as the output of any
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.\" document formatting or typesetting system, including
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.\" intermediate and printed output.
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.\"
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.\" This manual is distributed in the hope that it will be useful,
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.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
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.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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.\" GNU General Public License for more details.
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.\"
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.\" You should have received a copy of the GNU General Public
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.\" License along with this manual; if not, write to the Free
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.\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111,
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.\" USA.
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.\"
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.\" 1995-11-26 Markus Kuhn <mskuhn@cip.informatik.uni-erlangen.de>
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.\" First version written
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.\"
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.TH MUNLOCK 2 2003-08-21 "Linux 2.4" "Linux Programmer's Manual"
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.SH NAME
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munlock \- reenable paging for some parts of memory
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.SH SYNOPSIS
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.nf
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.B #include <sys/mman.h>
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.sp
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\fBint munlock(const void *\fIaddr\fB, size_t \fIlen\fB);
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.fi
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.SH DESCRIPTION
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.B munlock
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reenables paging for the memory in the range starting at
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.I addr
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with length
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.I len
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bytes. All pages which contain a part of the specified memory range
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can after calling
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.B munlock
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be moved to external swap space again by the kernel.
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Memory locks do not stack, i.e., pages which have been locked several times
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by calls to
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.B mlock
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or
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.B mlockall
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will be unlocked by a single call to
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.B munlock
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for the corresponding range or by
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.BR munlockall .
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Pages which are mapped to several locations or by several processes stay
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locked into RAM as long as they are locked at least at one location or by
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at least one process.
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On POSIX systems on which
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.B mlock
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and
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.B munlock
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are available,
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.B _POSIX_MEMLOCK_RANGE
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is defined in <unistd.h> and the value
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.B PAGESIZE
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from <limits.h> indicates the number of bytes per page.
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.SH "RETURN VALUE"
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On success,
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.B munlock
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returns zero. On error, \-1 is returned,
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.I errno
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is set appropriately, and no changes are made to any locks in the
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address space of the process.
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.SH ERRORS
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.TP
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.B EINVAL
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(Not on Linux)
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.I addr
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was not a multiple of the page size.
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.TP
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.B ENOMEM
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Some of the specified address range does not correspond to mapped
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pages in the address space of the process.
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.LP
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Linux adds
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.TP
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.B EINVAL
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.I len
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was negative.
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.SH "CONFORMING TO"
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POSIX.1b, SVr4
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.SH "SEE ALSO"
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.BR mlock (2),
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.BR mlockall (2),
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.BR munlockall (2)
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