/**************************************************************************** ** ** Copyright (C) 2016 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the QtCore module of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:LGPL$ ** Commercial License Usage ** Licensees holding valid commercial Qt licenses may use this file in ** accordance with the commercial license agreement provided with the ** Software or, alternatively, in accordance with the terms contained in ** a written agreement between you and The Qt Company. For licensing terms ** and conditions see https://www.qt.io/terms-conditions. For further ** information use the contact form at https://www.qt.io/contact-us. ** ** GNU Lesser General Public License Usage ** Alternatively, this file may be used under the terms of the GNU Lesser ** General Public License version 3 as published by the Free Software ** Foundation and appearing in the file LICENSE.LGPL3 included in the ** packaging of this file. Please review the following information to ** ensure the GNU Lesser General Public License version 3 requirements ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. ** ** GNU General Public License Usage ** Alternatively, this file may be used under the terms of the GNU ** General Public License version 2.0 or (at your option) the GNU General ** Public license version 3 or any later version approved by the KDE Free ** Qt Foundation. The licenses are as published by the Free Software ** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 ** included in the packaging of this file. Please review the following ** information to ensure the GNU General Public License requirements will ** be met: https://www.gnu.org/licenses/gpl-2.0.html and ** https://www.gnu.org/licenses/gpl-3.0.html. ** ** $QT_END_LICENSE$ ** ****************************************************************************/ /*! \class QQueue \inmodule QtCore \brief The QQueue class is a generic container that provides a queue. \ingroup tools \ingroup shared \reentrant QQueue\ is one of Qt's generic \l{container classes}. It implements a queue data structure for items of a same type. A queue is a first in, first out (FIFO) structure. Items are added to the tail of the queue using enqueue() and retrieved from the head using dequeue(). The head() function provides access to the head item without removing it. Example: \snippet code/src_corelib_tools_qqueue.cpp 0 The example will output 1, 2, 3 in that order. QQueue inherits from QList. All of QList's functionality also applies to QQueue. For example, you can use isEmpty() to test whether the queue is empty, and you can traverse a QQueue using QList's iterator classes (for example, QListIterator). But in addition, QQueue provides three convenience functions that make it easy to implement FIFO semantics: enqueue(), dequeue(), and head(). QQueue's value type must be an \l{assignable data type}. This covers most data types that are commonly used, but the compiler won't let you, for example, store a QWidget as a value. Use QWidget* instead. \sa QList, QStack */ /*! \fn template void QQueue::swap(QQueue &other) \since 4.8 Swaps queue \a other with this queue. This operation is very fast and never fails. */ /*! \fn template void QQueue::enqueue(const T& t) Adds value \a t to the tail of the queue. This is the same as QList::append(). \sa dequeue(), head() */ /*! \fn template T &QQueue::head() Returns a reference to the queue's head item. This function assumes that the queue isn't empty. This is the same as QList::first(). \sa dequeue(), enqueue(), isEmpty() */ /*! \fn template const T &QQueue::head() const \overload */ /*! \fn template T QQueue::dequeue() Removes the head item in the queue and returns it. This function assumes that the queue isn't empty. This is the same as QList::takeFirst(). \sa head(), enqueue(), isEmpty() */