187 lines
6.6 KiB
Perl
187 lines
6.6 KiB
Perl
.\" $NetBSD: 1.7.t,v 1.3 2003/08/07 10:30:49 agc Exp $
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.\"
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.\" Copyright (c) 1983, 1993, 1994
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)1.7.t 8.4 (Berkeley) 5/26/94
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.\"
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.Sh 2 "System operation support
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.LP
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Unless noted otherwise,
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the calls in this section are permitted only to a privileged user.
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.Sh 3 "Monitoring system operation
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.PP
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The
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.Fn sysctl
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function allows any process to retrieve system information
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and allows processes with appropriate privileges to set system configurations.
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.DS
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.Fd sysctl 6 "get or set system information
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sysctl(name, namelen, oldp, oldlenp, newp, newlen);
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int *name; u_int namelen; result void *oldp; result size_t *oldlenp;
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void *newp; size_t newlen;
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.DE
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The information available from
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.Fn sysctl
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consists of integers, strings, and tables.
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.Fn Sysctl
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returns a consistent snapshot of the data requested.
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Consistency is obtained by locking the destination
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buffer into memory so that the data may be copied out without blocking.
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Calls to
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.Fn sysctl
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are serialized to avoid deadlock.
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.PP
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The object to be interrogated or set is named
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using a ``Management Information Base'' (MIB)
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style name, listed in \fIname\fP,
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which is a \fInamelen\fP length array of integers.
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This name is from a hierarchical name space,
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with the most significant component in the first element of the array.
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It is analogous to a file pathname, but with integers as components
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rather than slash-separated strings.
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.PP
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The information is copied into the buffer specified by \fIoldp\fP.
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The size of the buffer is given by the location specified by \fIoldlenp\fP
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before the call,
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and that location is filled in with the amount of data copied after
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a successful call.
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If the amount of data available is greater
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than the size of the buffer supplied,
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the call supplies as much data as fits in the buffer provided
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and returns an error.
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.PP
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To set a new value, \fInewp\fP
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is set to point to a buffer of length \fInewlen\fP
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from which the requested value is to be taken.
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If a new value is not to be set, \fInewp\fP
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should be set to NULL and \fInewlen\fP set to 0.
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.PP
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The top level names (those used in the first element of the \fIname\fP array)
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are defined with a CTL_ prefix in \fI<sys/sysctl.h>\fP,
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and are as follows.
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The next and subsequent levels down are found
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in the include files listed here:
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.DS
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.TS
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l l l.
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Name Next Level Names Description
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_
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CTL\_DEBUG sys/sysctl.h Debugging
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CTL\_FS sys/sysctl.h Filesystem
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CTL\_HW sys/sysctl.h Generic CPU, I/O
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CTL\_KERN sys/sysctl.h High kernel limits
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CTL\_MACHDEP sys/sysctl.h Machine dependent
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CTL\_NET sys/socket.h Networking
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CTL\_USER sys/sysctl.h User-level
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CTL\_VM vm/vm_param.h Virtual memory
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.TE
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.DE
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.Sh 3 "Bootstrap operations
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.LP
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The call:
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.DS
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.Fd mount 4 "mount a filesystem
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mount(type, dir, flags, data);
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int type; char *dir; int flags; caddr_t data;
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.DE
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extends the name space. The
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.Fn mount
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call grafts a filesystem object onto the system file tree
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at the point specified in \fIdir\fP.
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The argument \fItype\fP specifies the type of filesystem to be mounted.
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The argument \fIdata\fP describes the filesystem object to be mounted
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according to the \fItype\fP.
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The contents of the filesystem become available through the
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new mount point \fIdir\fP.
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Any files in or below \fIdir\fP at the time of a successful mount
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disappear from the name space until the filesystem is unmounted.
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The \fIflags\fP value specifies generic properties,
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such as a request to mount the filesystem read-only.
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.LP
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Information about all mounted filesystems can be obtained with the call:
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.DS
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.Fd getfsstat 3 "get list of all mounted filesystems
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getfsstat(buf, bufsize, flags);
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result struct statfs *buf; long bufsize, int flags;
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.DE
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.LP
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The call:
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.DS
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.Fd swapon 1 "add a swap device for interleaved paging/swapping
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swapon(blkdev);
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char *blkdev;
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.DE
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specifies a device to be made available for paging and swapping.
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.Sh 3 "Shutdown operations
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.LP
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The call:
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.DS
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.Fd unmount 2 "dismount a filesystem
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unmount(dir, flags);
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char *dir; int flags;
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.DE
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unmounts the filesystem mounted on \fIdir\fP.
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This call will succeed only if the filesystem is
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not currently being used or if the MNT_FORCE flag is specified.
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.LP
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The call:
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.DS
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.Fd sync 0 "force completion of pending disk writes (flush cache)
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sync();
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.DE
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schedules I/O to flush all modified disk blocks resident in the kernel.
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(This call does not require privileged status.)
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Files can be selectively flushed to disk using the
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.Fn fsync
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call (see section
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.Xr 2.2.6 ).
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.LP
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The call:
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.DS
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.Fd reboot 1 "reboot system or halt processor
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reboot(how);
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int how;
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.DE
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causes a machine halt or reboot. The call may request a reboot
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by specifying \fIhow\fP as RB_AUTOBOOT, or that the machine be halted
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with RB_HALT, among other options.
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These constants are defined in \fI<sys/reboot.h>\fP.
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.Sh 3 "Accounting
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.PP
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The system optionally keeps an accounting record in a file
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for each process that exits on the system.
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The format of this record is beyond the scope of this document.
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The accounting may be enabled to a file \fIname\fP by doing:
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.DS
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.Fd acct 1 "enable or disable process accounting
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acct(path);
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char *path;
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.DE
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If \fIpath\fP is NULL, then accounting is disabled.
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Otherwise, the named file becomes the accounting file.
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