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/****************************************************************************
**
** Copyright (C) 2011 - 2012 Denis Shienkov <denis.shienkov@gmail.com>
** Contact: http://www.qt-project.org/legal
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:FDL$
** 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 Digia. For licensing terms and
** conditions see http://qt.digia.com/licensing. For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Free Documentation License Usage
** Alternatively, this file may be used under the terms of the GNU Free
** Documentation License version 1.3 as published by the Free Software
** Foundation and appearing in the file included in the packaging of
** this file. Please review the following information to ensure
** the GNU Free Documentation License version 1.3 requirements
** will be met: http://www.gnu.org/copyleft/fdl.html.
** $QT_END_LICENSE$
**
****************************************************************************/
/*!
\example terminal
\title Terminal Example
\ingroup qtserialport-examples
The Terminal example shows how to create a terminal for a simple serial
interface by using Qt Serial Port.
\image terminal-example.png Screenshot of the Terminal example
This example shows the main features of the QSerialPort class, like
configuration, I/O implementation and so forth. Also, the class
QSerialPortInfo is invoked to display information about the serial ports
available in the system.
QSerialPort supports two general programming approaches:
\list
\li \e{The asynchronous (non-blocking) approach.} Operations are scheduled
and performed when the control returns to Qt's event loop. QSerialPort emits
a signal when the operation is finished. For example, QSerialPort::write()
returns immediately. When the data is sent to the serial port, QSerialPort
emits \l{QSerialPort::bytesWritten()}{bytesWritten()}.
\li \e{The synchronous (blocking) approach.} In non-GUI and multithreaded
applications, the \c waitFor...() functions can be called (i.e.
QSerialPort::waitReadyRead()) to suspend the calling thread until the
operation has completed.
\endlist
In this example, the asynchronous approach is demonstrated. The
\l{examples/blockingterminal}{Blocking Simple Terminal} example
illustrates the synchronous approach.
Our example contains some GUI widgets:
\list
\li \l{examples/terminal/mainwindow.cpp}{MainWindow} - is the main application
window that contains all the working logic for the serial port programming,
including configuration, I/O processing and so forth, while inheriting the
QMainWindow.
\li \l{examples/terminal/console.cpp}{Console} - is the central widget of the
main window, displaying the transmitted or received data. The widget is
derived from the QPlainTextEdit class.
\li \l{examples/terminal/settingsdialog.cpp}{SettingsDialog} - is a dialog
for configuring the serial port, as well as for displaying the available
serial ports and information about them.
\endlist
The serial port is instantiated in the \l{examples/terminal/mainwindow.cpp}{MainWindow}
constructor. The main widget is passed as the parent, so the object deletion
happens automatically according to the the parent and child mechanism in Qt:
\snippet terminal/mainwindow.cpp 0
\dots
\snippet terminal/mainwindow.cpp 1
The only QSerialPort signal invoked in this example is
QSerialPort::readyRead(), which shows that new data has been received and
hence available:
\dots
\snippet terminal/mainwindow.cpp 2
\dots
\snippet terminal/mainwindow.cpp 3
Clicking on the \b{Connect} button invokes the \c openSerialPort() slot:
\snippet terminal/mainwindow.cpp 4
In this slot, the settings are read from \l{examples/terminal/settingsdialog.cpp}
{SettingsDialog} and an attempt is made to open and initialize the serial
port accordingly. If successful, the status bar displays a message that the
opening was successful with the given configuration; otherwise, a messagebox
is displayed with the appropriate error code and message. If the serial port
settings have never been called
\l{examples/terminal/settingsdialog.cpp}{SettingsDialog}, then the terminal
attempts to open the port with the default settings: 9600 8N1.
Clicking on the \b{Disconnect} button invokes the \c closeSerialPort()
slot:
\snippet terminal/mainwindow.cpp 5
In this case, handled by the closure of the serial port.
Typing characters in the console invokes the \c writeData() slot:
\snippet terminal/mainwindow.cpp 6
This slot sends the characters typed in the given
\l{examples/terminal/console.cpp}{Console} widget to the serial port.
When the serial port receives new data, the signal
\l{QTcpSocket::readyRead()}{readyRead()} is emitted, and that signal is
connected to the \c MainWindow::readData() slot:
\snippet terminal/mainwindow.cpp 7
This slot reads the data from the serial port and displays that in the
\l{examples/terminal/console.cpp}{Console} widget.
Clicking on the \b{Configure} button invokes the \c show() slot which
belongs to the \l{examples/terminal/settingsdialog.cpp}{SettingsDialog}
widget.
This method displays the \l{examples/terminal/settingsdialog.cpp}{SettingsDialog}
in which the user can choose the desired serial port, see the information
about the selected port, and set the desired parameters of the given serial
port.
\sa {Blocking Simple Terminal Example}
*/
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