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.\"     @(#)acct.2	8.1 (Berkeley) 6/4/93
.\" $FreeBSD$
.\"
.Dd April 17, 2004
.Dt ACCT 2
.Os
.Sh NAME
.Nm acct
.Nd enable or disable process accounting
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In unistd.h
.Ft int
.Fn acct "const char *file"
.Sh DESCRIPTION
The
.Fn acct
system call enables or disables the collection of system accounting
records.
If the argument
.Fa file
is a null pointer, accounting is disabled.
If
.Fa file
is an
.Em existing
pathname (null-terminated), record collection is enabled and for
every process initiated which terminates under normal
conditions an accounting record is appended to
.Fa file .
Abnormal conditions of termination are reboots
or other fatal system problems.
Records for processes which never terminate cannot be
produced by
.Fn acct .
.Pp
For more information on the record structure used by
.Fn acct ,
see
.In sys/acct.h
and
.Xr acct 5 .
.Pp
This call is permitted only to the super-user.
.Sh NOTES
Accounting is automatically disabled when the file system the
accounting file resides on runs out of space; it is enabled when
space once again becomes available.
The values controlling this behaviour can be modified using the following
.Xr sysctl 8
variables:
.Bl -tag -width ".Va kern.acct_chkfreq"
.It Va kern.acct_chkfreq
Specifies the frequency (in seconds) with which free disk
space should be checked.
.It Va kern.acct_resume
The percentage of free disk space above which process
accounting will resume.
.It Va kern.acct_suspend
The percentage of free disk space below which process
accounting will suspend.
.El
.Sh RETURN VALUES
On error -1 is returned.
The file must exist and the call may be exercised only by the super-user.
.Sh ERRORS
The
.Fn acct
system call will fail if one of the following is true:
.Bl -tag -width Er
.It Bq Er EPERM
The caller is not the super-user.
.It Bq Er ENOTDIR
A component of the path prefix is not a directory.
.It Bq Er ENAMETOOLONG
A component of a pathname exceeded 255 characters,
or an entire path name exceeded 1023 characters.
.It Bq Er ENOENT
The named file does not exist.
.It Bq Er EACCES
Search permission is denied for a component of the path prefix,
or the path name is not a regular file.
.It Bq Er ELOOP
Too many symbolic links were encountered in translating the pathname.
.It Bq Er EROFS
The named file resides on a read-only file system.
.It Bq Er EFAULT
The
.Fa file
argument
points outside the process's allocated address space.
.It Bq Er EIO
An I/O error occurred while reading from or writing to the file system.
.El
.Sh SEE ALSO
.Xr acct 5 ,
.Xr accton 8 ,
.Xr sa 8
.Sh HISTORY
The
.Fn acct
function appeared in
.At v7 .