text: //
  // RWLock_POSIX.h
  //
  // $Id: //poco/1.4/Foundation/include/Poco/RWLock_POSIX.h#1 $
  //
  // Library: Foundation
  // Package: Threading
  // Module:  RWLock
  //
  // Definition of the RWLockImpl class for POSIX Threads.
  //
  // 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_RWLock_POSIX_INCLUDED
  #define Foundation_RWLock_POSIX_INCLUDED
  
  
  #include "Poco/Foundation.h"
  #include "Poco/Exception.h"
  #include <pthread.h>
  #include <errno.h>
  
  
  namespace Poco {
  
  
  class Foundation_API RWLockImpl
  {
  protected:
  	RWLockImpl();
  	~RWLockImpl();
  	void readLockImpl();
  	bool tryReadLockImpl();
  	void writeLockImpl();
  	bool tryWriteLockImpl();
  	void unlockImpl();
  	
  private:
  	pthread_rwlock_t _rwl;
  };
  
  
  //
  // inlines
  //
  inline void RWLockImpl::readLockImpl()
  {
  	if (pthread_rwlock_rdlock(&_rwl)) 
  		throw SystemException("cannot lock reader/writer lock");
  }
  
  
  inline bool RWLockImpl::tryReadLockImpl()
  {
  	int rc = pthread_rwlock_tryrdlock(&_rwl);
  	if (rc == 0)
  		return true;
  	else if (rc == EBUSY)
  		return false;
  	else
  		throw SystemException("cannot lock reader/writer lock");
  
  }
  
  
  inline void RWLockImpl::writeLockImpl()
  {
  	if (pthread_rwlock_wrlock(&_rwl)) 
  		throw SystemException("cannot lock reader/writer lock");
  }
  
  
  inline bool RWLockImpl::tryWriteLockImpl()
  {
  	int rc = pthread_rwlock_trywrlock(&_rwl);
  	if (rc == 0)
  		return true;
  	else if (rc == EBUSY)
  		return false;
  	else
  		throw SystemException("cannot lock reader/writer lock");
  
  }
  
  
  inline void RWLockImpl::unlockImpl()
  {
  	if (pthread_rwlock_unlock(&_rwl))
  		throw SystemException("cannot unlock mutex");
  }
  
  
  } // namespace Poco
  
  
  #endif // Foundation_RWLock_POSIX_INCLUDED
  