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7.4 KiB
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182 lines
7.4 KiB
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<HTML>
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<META HTTP-EQUIV="CONTENT-TYPE" CONTENT="text/html; charset=utf-8">
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<TITLE>"SCHED_SETSCHEDULER"(P) manual page</TITLE>
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<META NAME="GENERATOR" CONTENT="OpenOffice.org 1.1.3 (Linux)">
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<META NAME="CREATED" CONTENT="20050505;13012200">
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</HEAD>
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<BODY LANG="en-GB" BGCOLOR="#ffffff" DIR="LTR">
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<H4>POSIX Threads for Windows – REFERENCE - <A HREF="http://sources.redhat.com/pthreads-win32">Pthreads-w32</A></H4>
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<P><A HREF="index.html">Reference Index</A></P>
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<P><A HREF="#toc">Table of Contents</A></P>
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<H2><A HREF="#toc0" NAME="sect0">Name</A></H2>
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<P>sched_setscheduler - set scheduling policy and parameters
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(<B>REALTIME</B>)
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</P>
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<H2><A HREF="#toc1" NAME="sect1">Synopsis</A></H2>
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<P><B>#include <sched.h> </B>
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</P>
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<P><B>int sched_setscheduler(pid_t</B> <I>pid</I><B>, int</B> <I>policy</I><B>,
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const struct sched_param *</B><I>param</I><B>); </B>
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</P>
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<H2><A HREF="#toc2" NAME="sect2">Description</A></H2>
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<P>The <B>sched_setscheduler</B> function shall set the scheduling
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policy and scheduling parameters of the process specified by <I>pid</I>
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to <I>policy</I> and the parameters specified in the <B>sched_param</B>
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structure pointed to by <I>param</I>, respectively. The value of the
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<I>sched_priority</I> member in the <B>sched_param</B> structure
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shall be any integer within the inclusive priority range for the
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scheduling policy specified by <I>policy</I>. If the value of <I>pid</I>
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is negative, the behavior of the <B>sched_setscheduler</B> function
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is unspecified.
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</P>
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<P>The possible values for the <I>policy</I> parameter are defined in
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the <I><sched.h></I> header.
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</P>
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<P><B>Pthreads-w32</B> only supports the <B>SCHED_OTHER</B> policy.
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Any other value for <I>policy</I> will return failure with errno set
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to <B>ENOSYS</B>. However, checks on <I>pid</I> and permissions are
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performed first so that the other useful side effects of this routine
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are retained.</P>
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<P>If a process specified by <I>pid</I> exists, and if the calling
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process has permission, the scheduling policy and scheduling
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parameters shall be set for the process whose process ID is equal to
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<I>pid</I>.
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</P>
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<P>If <I>pid</I> is zero, the scheduling policy and scheduling
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parameters shall be set for the calling process.
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</P>
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<P>Implementations may require that the requesting process have
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permission to set its own scheduling parameters or those of another
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process. Additionally, implementation-defined restrictions may apply
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as to the appropriate privileges required to set a process’ own
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scheduling policy, or another process’ scheduling policy, to a
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particular value.
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</P>
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<P>The <B>sched_setscheduler</B> function shall be considered
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successful if it succeeds in setting the scheduling policy and
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scheduling parameters of the process specified by <I>pid</I> to the
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values specified by <I>policy</I> and the structure pointed to by
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<I>param</I>, respectively.
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</P>
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<P>The effect of this function on individual threads is dependent on
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the scheduling contention scope of the threads:
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</P>
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<DL>
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<DT>*
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</DT><DD STYLE="margin-bottom: 0.5cm">
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For threads with system scheduling contention scope, these functions
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shall have no effect on their scheduling.
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</DD><DT>
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*
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</DT><DD STYLE="margin-bottom: 0.5cm">
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For threads with process scheduling contention scope, the threads’
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scheduling policy and associated parameters shall not be affected.
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However, the scheduling of these threads with respect to threads in
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other processes may be dependent on the scheduling parameters of
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their process, which are governed using these functions.
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</DD></DL>
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<P>
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This function is not atomic with respect to other threads in the
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process. Threads may continue to execute while this function call is
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in the process of changing the scheduling policy and associated
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scheduling parameters for the underlying kernel-scheduled entities
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used by the process contention scope threads.
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</P>
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<H2><A HREF="#toc3" NAME="sect3">Return Value</A></H2>
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<P>Upon successful completion, the function shall return the former
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scheduling policy of the specified process. If the <B>sched_setscheduler</B>
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function fails to complete successfully, the policy and scheduling
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parameters shall remain unchanged, and the function shall return a
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value of -1 and set <I>errno</I> to indicate the error.
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</P>
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<H2><A HREF="#toc4" NAME="sect4">Errors</A></H2>
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<P>The <B>sched_setscheduler</B> function shall fail if:
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</P>
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<DL>
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<DT><B>EINVAL</B>
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</DT><DD>
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The value of the <I>policy</I> parameter is invalid, or one or more
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of the parameters contained in <I>param</I> is outside the valid
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range for the specified scheduling policy.
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</DD><DT>
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<B>EPERM</B>
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</DT><DD>
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The requesting process does not have permission to set either or
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both of the scheduling parameters or the scheduling policy of the
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specified process.
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</DD><DT>
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<B>ESRCH</B>
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</DT><DD STYLE="margin-bottom: 0.5cm">
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No process can be found corresponding to that specified by <I>pid</I>.
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</DD></DL>
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<P>
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<I>The following sections are informative.</I>
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</P>
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<H2><A HREF="#toc5" NAME="sect5">Examples</A></H2>
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<P>None.
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</P>
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<H2><A HREF="#toc6" NAME="sect6">Application Usage</A></H2>
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<P>None.
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</P>
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<H2><A HREF="#toc7" NAME="sect7">Rationale</A></H2>
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<P>None.
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</P>
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<H2><A HREF="#toc8" NAME="sect8">Future Directions</A></H2>
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<P>None.
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</P>
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<H2><A HREF="#toc9" NAME="sect9">See Also</A></H2>
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<P><A HREF="sched_getscheduler.html"><B>sched_getscheduler</B>(3)</A>
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<B>,</B> the Base Definitions volume of IEEE Std 1003.1-2001,
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<I><sched.h></I>
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</P>
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<H2><A HREF="#toc10" NAME="sect10">Copyright</A></H2>
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<P>Portions of this text are reprinted and reproduced in electronic
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form from IEEE Std 1003.1, 2003 Edition, Standard for Information
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Technology -- Portable Operating System Interface (POSIX), The Open
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Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the
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Institute of Electrical and Electronics Engineers, Inc and The Open
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Group. In the event of any discrepancy between this version and the
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original IEEE and The Open Group Standard, the original IEEE and The
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Open Group Standard is the referee document. The original Standard
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can be obtained online at <A HREF="http://www.opengroup.org/unix/online.html">http://www.opengroup.org/unix/online.html</A>
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.
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</P>
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<P>Modified by Ross Johnson for use with <A HREF="http://sources.redhat.com/pthreads-win32">Pthreads-w32</A>.</P>
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<HR>
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<P><A NAME="toc"></A><B>Table of Contents</B></P>
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<UL>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect0" NAME="toc0">Name</A>
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</P>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect1" NAME="toc1">Synopsis</A>
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</P>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect2" NAME="toc2">Description</A>
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</P>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect3" NAME="toc3">Return
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Value</A>
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</P>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect4" NAME="toc4">Errors</A>
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</P>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect5" NAME="toc5">Examples</A>
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</P>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect6" NAME="toc6">Application
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Usage</A>
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</P>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect7" NAME="toc7">Rationale</A>
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</P>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect8" NAME="toc8">Future
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Directions</A>
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</P>
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<LI><P STYLE="margin-bottom: 0cm"><A HREF="#sect9" NAME="toc9">See
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Also</A>
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</P>
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<LI><P><A HREF="#sect10" NAME="toc10">Copyright</A>
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</P>
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</UL>
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</BODY>
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</HTML>
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