thread.h

C++ class libraries for network-centric, portable applications, integrated perfectly with the C++ St

//
// Thread.h
//
// $Id: //poco/1.2/Foundation/include/Poco/Thread.h#1 $
//
// Library: Foundation
// Package: Threading
// Module:  Thread
//
// Definition of the Thread class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
// 
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//


#ifndef Foundation_Thread_INCLUDED
#define Foundation_Thread_INCLUDED


#include "Poco/Foundation.h"


#if defined(POCO_OS_FAMILY_WINDOWS)
#include "Poco/Thread_WIN32.h"
#else
#include "Poco/Thread_POSIX.h"
#endif


namespace Poco {


class Runnable;
class ThreadLocalStorage;


class Foundation_API Thread: private ThreadImpl
	/// This class implements a platform-independent
	/// wrapper to an operating system thread.
	///
	/// Every Thread object gets a unique (within
	/// its process) numeric thread ID.
	/// Furthermore, a thread can be assigned a name.
{
public:	
	enum Priority
		/// Thread priorities.
	{
		PRIO_LOWEST  = PRIO_LOWEST_IMPL, /// The lowest thread priority.
		PRIO_LOW     = PRIO_LOW_IMPL,    /// A lower than normal thread priority.
		PRIO_NORMAL  = PRIO_NORMAL_IMPL, /// The normal thread priority.
		PRIO_HIGH    = PRIO_HIGH_IMPL,   /// A higher than normal thread priority.
		PRIO_HIGHEST = PRIO_HIGHEST_IMPL /// The highest thread priority.
	};

	Thread();
		/// Creates a thread. Call start() to start it.
		
	Thread(const std::string& name);
		/// Creates a named thread. Call start() to start it.
		
	~Thread();
		/// Destroys the thread.

	int id() const;
		/// Returns the unique thread ID of the thread.

	const std::string& name() const;
		/// Returns the name of the thread.

	void setPriority(Priority prio);
		/// Sets the thread's priority.
		///
		/// Some platform only allow changing a thread's priority
		/// if the process has certain privileges.

	Priority getPriority() const;
		/// Returns the thread's priority.

	void start(Runnable& target);
		/// Starts the thread with the given target.

	void join();
		/// Waits until the thread completes execution.	
		/// If multiple threads try to join the same
		/// thread, the result is undefined.

	bool isRunning() const;
		/// Returns true if the thread is running.

	static void sleep(long milliseconds);
		/// Suspends the current thread for the specified
		/// amount of time.

	static void yield();
		/// Yields cpu to other threads.

	static Thread* current();
		/// Returns the Thread object for the currently active thread.
		/// If the current thread is the main thread, 0 is returned.

protected:
	ThreadLocalStorage& tls();
		/// Returns a reference to the thread's local storage.

	void clearTLS();
		/// Clears the thread's local storage.

	std::string makeName();
		/// Creates a unique name for a thread.
		
	static int uniqueId();
		/// Creates and returns a unique id for a thread.
		
	void setName(const std::string& name);
		/// Sets the name of the thread.

private:
	Thread(const Thread&);
	Thread& operator = (const Thread&);

	int                 _id;
	std::string         _name;
	ThreadLocalStorage* _pTLS;

	friend class ThreadLocalStorage;
	friend class PooledThread;
};


//
// inlines
//
inline int Thread::id() const
{
	return _id;
}


inline const std::string& Thread::name() const
{
	return _name;
}


inline bool Thread::isRunning() const
{
	return isRunningImpl();
}


inline void Thread::sleep(long milliseconds)
{
	sleepImpl(milliseconds);
}


inline void Thread::yield()
{
	yieldImpl();
}


inline Thread* Thread::current()
{
	return static_cast<Thread*>(currentImpl());
}


} // namespace Poco


#endif // Foundation_Thread_INCLUDED