genericopenlibs/openenvcore/libc/src/nice.cpp
author Dremov Kirill (Nokia-D-MSW/Tampere) <kirill.dremov@nokia.com>
Mon, 04 Oct 2010 02:56:42 +0300
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// Copyright (c) 2005-2009 Nokia Corporation and/or its subsidiary(-ies).
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// All rights reserved.
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// This component and the accompanying materials are made available
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// under the terms of "Eclipse Public License v1.0"
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// which accompanies this distribution, and is available
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// at the URL "http://www.eclipse.org/legal/epl-v10.html".
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//
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// Initial Contributors:
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// Nokia Corporation - initial contribution.
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//
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// Contributors:
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//
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// Description:
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// Name        : nice.cpp
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// Part of     : LIBC
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// Contains the source for fchdir
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// Version     : 1.0
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//
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#include <sys/time.h>
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#include <sys/resource.h>
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#include <errno.h>
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#include <e32std.h>
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#include <e32const.h>
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#include <unistd.h>
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extern "C" {
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/*
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The function nice() increases or decreases the priority value by
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adding the value 'incr' to the current priority.
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It internally uses getpriority and setpriority to set the priority 
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to new value.
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It returns the new value of the priority, which shall be in the range 
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of -15 to 19. -1 is a legitimate return value, so the user has to check 
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the errno to be sure of failure.
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*/
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EXPORT_C int nice(int incr)
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	{
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	int retGetPri = -1;
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	int retSetPri = -1;
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	int retVal 	  = -1;
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	if(((retGetPri = getpriority(PRIO_PROCESS, 0)) == -1) && (errno))
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		{
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		errno = ENOSYS;
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		}
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	else
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		{
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		retSetPri = setpriority(PRIO_PROCESS, 0, retGetPri + incr);
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		if(!retSetPri)
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			{
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			retVal = 0;
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			}
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		}
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	return retVal;
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	}
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} //extern "C"