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 ** GNU General Public License Usage
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 #include "qtlockedfile.h"
 
 namespace SharedTools {
 
 /*!
     \class QtLockedFile
 
     \brief The QtLockedFile class extends QFile with advisory locking functions.
 
     A file may be locked in read or write mode. Multiple instances of
     \e QtLockedFile, created in multiple processes running on the same
     machine, may have a file locked in read mode. Exactly one instance
     may have it locked in write mode. A read and a write lock cannot
     exist simultaneously on the same file.
 
     The file locks are advisory. This means that nothing prevents
     another process from manipulating a locked file using QFile or
     file system functions offered by the OS. Serialization is only
     guaranteed if all processes that access the file use
     QtLockedFile. Also, while holding a lock on a file, a process
     must not open the same file again (through any API), or locks
     can be unexpectedly lost.
 
     The lock provided by an instance of \e QtLockedFile is released
     whenever the program terminates. This is true even when the
     program crashes and no destructors are called.
 */
 
 /*! \enum QtLockedFile::LockMode
 
     This enum describes the available lock modes.
 
     \value ReadLock A read lock.
     \value WriteLock A write lock.
     \value NoLock Neither a read lock nor a write lock.
 */
 
 /*!
     Constructs an unlocked \e QtLockedFile object. This constructor behaves in the same way
     as \e QFile::QFile().
 
     \sa QFile::QFile()
 */
 QtLockedFile::QtLockedFile()
     : QFile()
     , m_lock_mode(NoLock)
 {
 #ifdef Q_OS_WIN
     m_semaphore_hnd = 0;
     m_mutex_hnd = 0;
 #endif
 }
 
 /*!
     Constructs an unlocked QtLockedFile object with file \a name. This constructor behaves in
     the same way as \e QFile::QFile(const QString&).
 
     \sa QFile::QFile()
 */
 QtLockedFile::QtLockedFile(const QString &name)
     : QFile(name)
     , m_lock_mode(NoLock)
 {
 #ifdef Q_OS_WIN
     m_semaphore_hnd = 0;
     m_mutex_hnd = 0;
 #endif
 }
 
 /*!
     Returns \e true if this object has a in read or write lock;
     otherwise returns \e false.
 
     \sa lockMode()
 */
 bool QtLockedFile::isLocked() const
 {
     return m_lock_mode != NoLock;
 }
 
 /*!
     Returns the type of lock currently held by this object, or \e QtLockedFile::NoLock.
 
     \sa isLocked()
 */
 QtLockedFile::LockMode QtLockedFile::lockMode() const
 {
     return m_lock_mode;
 }
 
 /*!
     \fn bool QtLockedFile::lock(LockMode mode, bool block = true)
 
     Obtains a lock of type \a mode.
 
     If \a block is true, this
     function will block until the lock is acquired. If \a block is
     false, this function returns \e false immediately if the lock cannot
     be acquired.
 
     If this object already has a lock of type \a mode, this function returns \e true immediately. If this object has a lock of a different type than \a mode, the lock
     is first released and then a new lock is obtained.
 
     This function returns \e true if, after it executes, the file is locked by this object,
     and \e false otherwise.
 
     \sa unlock(), isLocked(), lockMode()
 */
 
 /*!
     \fn bool QtLockedFile::unlock()
 
     Releases a lock.
 
     If the object has no lock, this function returns immediately.
 
     This function returns \e true if, after it executes, the file is not locked by
     this object, and \e false otherwise.
 
     \sa lock(), isLocked(), lockMode()
 */
 
 /*!
     \fn QtLockedFile::~QtLockedFile()
 
     Destroys the \e QtLockedFile object. If any locks were held, they are released.
 */
 
 } // namespace SharedTools