The QIODevice class is the base interface class of all I/O devices in Qt. More...

Inheritance diagram for QtCore.QIODevice:

[legend]

Collaboration diagram for QtCore.QIODevice:

Public Types
enum	OpenModeFlag { Append = 4, NotOpen = 0, ReadOnly = 1, ReadWrite = 3, Text = 16, Truncate = 8, Unbuffered = 32, WriteOnly = 2 }
	More...

Public Member Functions
	QIODevice ()


	QIODevice (QObject parent)


override void	CreateProxy ()

virtual bool	AtEnd ()


virtual long	BytesAvailable ()


virtual long	BytesToWrite ()


virtual bool	CanReadLine ()


virtual void	Close ()


new string	ErrorString ()


new bool	GetChar (Pointer< sbyte > c)


new bool	IsOpen ()


new bool	IsReadable ()


virtual bool	IsSequential ()


new bool	IsTextModeEnabled ()


new bool	IsWritable ()


virtual bool	Open (QIODevice.OpenModeFlag mode)


new QIODevice.OpenModeFlag	OpenMode ()


new QByteArray	Peek (long maxlen)


new long	Peek (Pointer< sbyte > data, long maxlen)


virtual long	Pos ()


new bool	PutChar (sbyte c)


new QByteArray	Read (long maxlen)


new long	Read (Pointer< sbyte > data, long maxlen)


new QByteArray	ReadAll ()


new QByteArray	ReadLine (long maxlen=0)


new long	ReadLine (Pointer< sbyte > data, long maxlen)


virtual bool	Reset ()


virtual bool	Seek (long pos)


new void	SetTextModeEnabled (bool enabled)


virtual long	Size ()


new void	UngetChar (sbyte c)


virtual bool	WaitForBytesWritten (int msecs)


virtual bool	WaitForReadyRead (int msecs)


new long	Write (QByteArray data)


new long	Write (string data)


new long	Write (string data, long len)


new void	Dispose ()

Public Member Functions inherited from QtCore.QObject
	QObject (QObject parent=null)


new bool	BlockSignals (bool b)


new System.Collections.Generic.List < QObject >	Children ()


new bool	Connect (QObject sender, string signal, string member, Qt.ConnectionType type=Qt.ConnectionType.AutoConnection)


new void	DeleteLater ()


new bool	Disconnect (QObject receiver, string member=null)


new bool	Disconnect (string signal=null, QObject receiver=null, string member=null)


new void	DumpObjectInfo ()


new void	DumpObjectTree ()


new System.Collections.Generic.List < QByteArray >	DynamicPropertyNames ()


virtual bool	OnEvent (QEvent arg1)


virtual bool	EventFilter (QObject arg1, QEvent arg2)


new bool	Inherits (string classname)


new void	InstallEventFilter (QObject arg1)


new bool	IsWidgetType ()


new void	KillTimer (int id)


new object	Property (string name)


new void	RemoveEventFilter (QObject arg1)


new bool	SetProperty (string name, object value)


new void	SetUserData (uint id, QObjectUserData data)

new bool	SignalsBlocked ()


new int	StartTimer (int interval)


new QObjectUserData	UserData (uint id)

new void	Dispose ()

Public Member Functions inherited from QtCore.Qt
delegate QTextStream	FuncQTextStreamQTextStream (QTextStream qTextStream)

delegate string	FuncStringQByteArray (QByteArray qByteArray)

delegate QByteArray	FuncQByteArrayString (string @string)

delegate void	ActionQtMsgTypeString (QtMsgType qtMsgType, string @string)

delegate QObject	FuncQObject ()

Static Public Member Functions
static string	Tr (string s, string c=null)

static string	Tr (string s, string c, int n)

static string	TrUtf8 (string s, string c=null)

static string	TrUtf8 (string s, string c, int n)

Static Public Member Functions inherited from QtCore.QObject
static bool	Connect (QObject sender, QMetaMethod signal, QObject receiver, QMetaMethod method, Qt.ConnectionType type=Qt.ConnectionType.AutoConnection)


static bool	Connect (QObject sender, string signal, QObject receiver, string member, Qt.ConnectionType arg5=Qt.ConnectionType.AutoConnection)


static bool	Disconnect (QObject sender, QMetaMethod signal, QObject receiver, QMetaMethod member)


static bool	Disconnect (QObject sender, string signal, QObject receiver, string member)


static uint	RegisterUserData ()

static string	Tr (string s, string c=null)


static string	Tr (string s, string c, int n)


static string	TrUtf8 (string s, string c=null)


static string	TrUtf8 (string s, string c, int n)


Static Public Member Functions inherited from QtCore.Qt
static QDataStream	Write (QDataStream s, object p)

static QDataStream	Write (QDataStream arg1, QSizeF arg2)

static QTextStream	Write (QTextStream s, Qt.FuncQTextStreamQTextStream f)

static QDataStream	Write (QDataStream arg1, QPoint arg2)

static QDataStream	Write (QDataStream arg1, QLineF arg2)

static QDataStream	Write (QDataStream arg1, QPointF arg2)

static QDataStream	Write (QDataStream arg1, QChar arg2)

static QDataStream	Write (QDataStream arg1, QByteArray arg2)

static QDataStream	Write (QDataStream arg1, QEasingCurve arg2)

static QDataStream	Write (QDataStream arg1, QRectF arg2)

static QDataStream	Write (QDataStream arg1, QDateTime arg2)

static QDataStream	Write (QDataStream arg1, QUrl arg2)

static QDataStream	Write (QDataStream arg1, QTime arg2)

static QDataStream	Write (QDataStream arg1, QLocale arg2)

static QDataStream	Write (QDataStream arg1, QBitArray arg2)

static QDataStream	Write (QDataStream arg1, QUuid arg2)

static QDataStream	Write (QDataStream arg1, QLine arg2)

static QDataStream	Write (QDataStream arg1, QDate arg2)

static QDataStream	Write (QDataStream @out, QRegExp regExp)

static QDataStream	Write (QDataStream arg1, QRect arg2)

static QDataStream	Write (QDataStream arg1, QSize arg2)

static QDataStream	Write (QDataStream s, QVariant.Type p)

static QDataStream	Write (QDataStream arg1, string arg2)

static QDataStream	Write (QDataStream @out, System.Collections.Generic.List< string > list)

static QDataStream	Read (QDataStream arg1, QChar arg2)

static QDataStream	Read (QDataStream arg1, QLocale arg2)

static QDataStream	Read (QDataStream arg1, QRect arg2)

static QDataStream	Read (QDataStream arg1, QEasingCurve arg2)

static QDataStream	Read (QDataStream arg1, QDate arg2)

static QDataStream	Read (QDataStream arg1, QUrl arg2)

static QDataStream	Read (QDataStream arg1, QUuid arg2)

static QTextStream	Read (QTextStream s, Qt.FuncQTextStreamQTextStream f)

static QDataStream	Read (QDataStream arg1, QLineF arg2)

static QDataStream	Read (QDataStream arg1, QRectF arg2)

static QDataStream	Read (QDataStream arg1, QPointF arg2)

static QDataStream	Read (QDataStream arg1, QLine arg2)

static QDataStream	Read (QDataStream arg1, QBitArray arg2)

static QDataStream	Read (QDataStream arg1, QSize arg2)

static QDataStream	Read (QDataStream arg1, QDateTime arg2)

static QDataStream	Read (QDataStream arg1, QTime arg2)

static QDataStream	Read (QDataStream arg1, QPoint arg2)

static QDataStream	Read (QDataStream @in, QRegExp regExp)

static QDataStream	Read (QDataStream s, object p)

static QDataStream	Read (QDataStream arg1, QByteArray arg2)

static QDataStream	Read (QDataStream arg1, QSizeF arg2)

static QDataStream	Read (QDataStream arg1, string arg2)

static QDataStream	Read (QDataStream s, QVariant.Type p)

static QDataStream	Read (QDataStream @in, System.Collections.Generic.List< string > list)

static double	qAcos (double v)

static void	qAddPostRoutine (System.Action arg1)

static string	qAppName ()

static double	qAsin (double v)

static double	qAtan (double v)

static double	qAtan2 (double x, double y)

static void	qBadAlloc ()

static int	qCeil (double v)

static ushort	qChecksum (string s, uint len)

static QByteArray	qCompress (QByteArray data)

static QByteArray	qCompress (QByteArray data, int compressionLevel=-1)

static QByteArray	qCompress (Pointer< byte > data, int nbytes)

static QByteArray	qCompress (Pointer< byte > data, int nbytes, int compressionLevel=-1)

static double	qCos (double v)

static double	qExp (double v)

static double	qFabs (double v)

static double	qFastCos (double x)

static double	qFastSin (double x)

static string	qFlagLocation (string method)

static int	qFloor (double v)

static bool	qFuzzyCompare (double p1, double p2)

static bool	qFuzzyCompare (float p1, float p2)

static bool	qFuzzyIsNull (double d)

static bool	qFuzzyIsNull (float f)

static uint	qHash (QBitArray key)

static uint	qHash (QChar key)

static uint	qHash (QStringRef key)

static uint	qHash (QUrl url)

static uint	qHash (QPersistentModelIndex index)

static uint	qHash (QByteArray key)

static uint	qHash (QModelIndex index)

static uint	qHash (uint key)

static uint	qHash (sbyte key)

static uint	qHash (byte key)

static uint	qHash (short key)

static uint	qHash (NativeLong key)

static uint	qHash (ushort key)

static uint	qHash (long key)

static uint	qHash (ulong key)

static uint	qHash (int key)

static uint	qHash (string key)

static uint	qHash (NativeULong key)

static double	qInf ()

static Qt.ActionQtMsgTypeString	qInstallMsgHandler (Qt.ActionQtMsgTypeString arg1)

static int	qIntCast (float f)

static int	qIntCast (double f)

static bool	qIsFinite (double d)

static bool	qIsFinite (float f)

static bool	qIsInf (float f)

static bool	qIsInf (double d)

static bool	qIsNaN (float f)

static bool	qIsNaN (double d)

static bool	qIsNull (float f)

static bool	qIsNull (double d)

static double	qLn (double v)

static double	qPow (double x, double y)

static double	qQNaN ()

static void	qRegisterStaticPluginInstanceFunction (Qt.FuncQObject function)

static void	qRemovePostRoutine (System.Action arg1)

static int	qRound (double d)

static long	qRound64 (double d)

static double	qSNaN ()

static bool	qSharedBuild ()

static double	qSin (double v)

static double	qSqrt (double v)

static bool	qStringComparisonHelper (QStringRef s1, string s2)

static double	qTan (double v)

static QByteArray	qUncompress (QByteArray data)

static QByteArray	qUncompress (Pointer< byte > data, int nbytes)

static string	qVersion ()

static void	Qbswap_helper (Pointer< byte > src, Pointer< byte > dest, int size)

static QByteArray	Qgetenv (string varName)

static bool	Qputenv (string varName, QByteArray value)

static int	Qrand ()

static void	Qsrand (uint seed)

static int	Qstrcmp (QByteArray str1, QByteArray str2)

static int	Qstrcmp (QByteArray str1, string str2)

static int	Qstrcmp (string str1, QByteArray str2)

static int	Qstrcmp (string str1, string str2)

static Pointer< sbyte >	Qstrcpy (Pointer< sbyte > dst, string src)

static Pointer< sbyte >	Qstrdup (string arg1)

static int	Qstricmp (string arg1, string arg2)

static uint	Qstrlen (string str)

static int	Qstrncmp (string str1, string str2, uint len)

static Pointer< sbyte >	Qstrncpy (Pointer< sbyte > dst, string src, uint len)

static int	Qstrnicmp (string arg1, string arg2, uint len)

static uint	Qstrnlen (string str, uint maxlen)

static string	QtTrId (string id, int n=-1)

Protected Member Functions
	QIODevice (System.Type dummy)

new void	OnAboutToClose ()


new void	OnBytesWritten (long bytes)


new void	OnReadChannelFinished ()


abstract long	ReadData (Pointer< sbyte > data, long maxlen)


virtual long	ReadLineData (Pointer< sbyte > data, long maxlen)


new void	OnReadyRead ()


new void	SetErrorString (string errorString)


new void	SetOpenMode (QIODevice.OpenModeFlag openMode)


abstract long	WriteData (string data, long len)


Protected Member Functions inherited from QtCore.QObject
	QObject (System.Type dummy)

virtual void	OnChildEvent (QChildEvent arg1)


virtual void	ConnectNotify (string signal)


virtual void	OnCustomEvent (QEvent arg1)


new void	OnDestroyed (QObject arg1=null)


virtual void	DisconnectNotify (string signal)


new int	Receivers (string signal)


new QObject	Sender ()


new int	SenderSignalIndex ()


virtual void	OnTimerEvent (QTimerEvent arg1)

Properties
Slot	ReadyRead


Slot< System.Int64 >	BytesWritten


Slot	AboutToClose


Slot	ReadChannelFinished


static new QMetaObject	StaticMetaObject `[get]`

new IQIODeviceSignals	Emit `[get]`

Properties inherited from QtCore.QObject
virtual EventHandler < QEventArgs< QChildEvent > >	ChildEvent


virtual EventHandler < QEventArgs< QEvent > >	CustomEvent


virtual EventHandler < QEventArgs< QEvent > >	Event


virtual EventHandler < QEventArgs< QTimerEvent > >	TimerEvent


Slot< QObject >	DestroyedQObject

Slot	Destroyed


new QObject	Parent `[get, set]`


virtual System.IntPtr	SmokeObject `[get, set]`

new string	ObjectName `[get, set]`


static new QMetaObject	StaticMetaObject `[get]`


static new QMetaObject	StaticQtMetaObject `[get]`

new IQObjectSignals	Emit `[get]`

Additional Inherited Members
Protected Attributes inherited from QtCore.QObject
object	Q_EMIT = null

SmokeInvocation	interceptor

readonly List< QEventHandler >	eventFilters = new List<QEventHandler>()

Detailed Description

The QIODevice class is the base interface class of all I/O devices in Qt.

QIODevice provides both a common implementation and an abstract interface for devices that support reading and writing of blocks of data, such as QFile, QBuffer and QTcpSocket. QIODevice is abstract and can not be instantiated, but it is common to use the interface it defines to provide device-independent I/O features. For example, Qt's XML classes operate on a QIODevice pointer, allowing them to be used with various devices (such as files and buffers).

Before accessing the device, open() must be called to set the correct OpenMode (such as ReadOnly or ReadWrite). You can then write to the device with write() or putChar(), and read by calling either read(), readLine(), or readAll(). Call close() when you are done with the device.

QIODevice distinguishes between two types of devices: random-access devices and sequential devices.

Random-access devices support seeking to arbitrary positions using seek(). The current position in the file is available by calling pos(). QFile and QBuffer are examples of random-access devices.

Sequential devices don't support seeking to arbitrary positions. The data must be read in one pass. The functions pos() and size() don't work for sequential devices. QTcpSocket and QProcess are examples of sequential devices.

You can use isSequential() to determine the type of device.

QIODevice emits readyRead() when new data is available for reading; for example, if new data has arrived on the network or if additional data is appended to a file that you are reading from. You can call bytesAvailable() to determine the number of bytes that are currently available for reading. It's common to use bytesAvailable() together with the readyRead() signal when programming with asynchronous devices such as QTcpSocket, where fragments of data can arrive at arbitrary points in time. QIODevice emits the bytesWritten() signal every time a payload of data has been written to the device. Use bytesToWrite() to determine the current amount of data waiting to be written.

Certain subclasses of QIODevice, such as QTcpSocket and QProcess, are asynchronous. This means that I/O functions such as write() or read() always return immediately, while communication with the device itself may happen when control goes back to the event loop. QIODevice provides functions that allow you to force these operations to be performed immediately, while blocking the calling thread and without entering the event loop. This allows QIODevice subclasses to be used without an event loop, or in a separate thread:

waitForReadyRead() - This function suspends operation in the calling thread until new data is available for reading.

waitForBytesWritten() - This function suspends operation in the calling thread until one payload of data has been written to the device.

waitFor....() - Subclasses of QIODevice implement blocking functions for device-specific operations. For example, QProcess has a function called waitForStarted() which suspends operation in the calling thread until the process has started.

Calling these functions from the main, GUI thread, may cause your user interface to freeze. Example:

QProcess gzip;

gzip.start("gzip", QStringList() << "-c");

if (!gzip.waitForStarted())

return false;

gzip.write("uncompressed data");

QByteArray compressed;

while (gzip.waitForReadyRead())

compressed += gzip.readAll();

By subclassing QIODevice, you can provide the same interface to your own I/O devices. Subclasses of QIODevice are only required to implement the protected readData() and writeData() functions. QIODevice uses these functions to implement all its convenience functions, such as getChar(), readLine() and write(). QIODevice also handles access control for you, so you can safely assume that the device is opened in write mode if writeData() is called.

Some subclasses, such as QFile and QTcpSocket, are implemented using a memory buffer for intermediate storing of data. This reduces the number of required device accessing calls, which are often very slow. Buffering makes functions like getChar() and putChar() fast, as they can operate on the memory buffer instead of directly on the device itself. Certain I/O operations, however, don't work well with a buffer. For example, if several users open the same device and read it character by character, they may end up reading the same data when they meant to read a separate chunk each. For this reason, QIODevice allows you to bypass any buffering by passing the Unbuffered flag to open(). When subclassing QIODevice, remember to bypass any buffer you may use when the device is open in Unbuffered mode.

See also QBuffer, QFile, and QTcpSocket.

Member Enumeration Documentation

enum QtCore.QIODevice.OpenModeFlag

This enum is used with open() to describe the mode in which a device is opened. It is also returned by openMode().

Certain flags, such as Unbuffered and Truncate, are meaningless when used with some subclasses. Some of these restrictions are implied by the type of device that is represented by a subclass. In other cases, the restriction may be due to the implementation, or may be imposed by the underlying platform; for example, QTcpSocket does not support Unbuffered mode, and limitations in the native API prevent QFile from supporting Unbuffered on Windows.

Enumerator:

Append	The device is opened in append mode, so that all data is written to the end of the file.
NotOpen	The device is not open.
ReadOnly	The device is open for reading.
ReadWrite	The device is open for reading and writing.
Text	When reading, the end-of-line terminators are translated to '\n'. When writing, the end-of-line terminators are translated to the local encoding, for example '\r\n' for Win32.
Truncate	If possible, the device is truncated before it is opened. All earlier contents of the device are lost.
Unbuffered	Any buffer in the device is bypassed.
WriteOnly	The device is open for writing.

Constructor & Destructor Documentation

QtCore.QIODevice.QIODevice ( System.Type dummy )

protected

QtCore.QIODevice.QIODevice ( )

Constructs a QIODevice object.

QtCore.QIODevice.QIODevice ( QObject parent )

Constructs a QIODevice object with the given parent.

Member Function Documentation

virtual bool QtCore.QIODevice.AtEnd ( )

virtual

Returns true if the current read and write position is at the end of the device (i.e. there is no more data available for reading on the device); otherwise returns false.

For some devices, atEnd() can return true even though there is more data to read. This special case only applies to devices that generate data in direct response to you calling read() (e.g., /dev or /proc files on Unix and Mac OS X, or console input / stdin on all platforms).

See also bytesAvailable(), read(), and isSequential().

Reimplemented in QtCore.QProcess, QtCore.QFile, QtNetwork.QSslSocket, QtCore.QBuffer, and QtNetwork.QAbstractSocket.

virtual long QtCore.QIODevice.BytesAvailable ( )

virtual

Returns the number of bytes that are available for reading. This function is commonly used with sequential devices to determine the number of bytes to allocate in a buffer before reading.

Subclasses that reimplement this function must call the base implementation in order to include the size of QIODevices' buffer. Example:

qint64 CustomDevice::bytesAvailable() const

{

return buffer.size() + QIODevice::bytesAvailable();

}

See also bytesToWrite(), readyRead(), and isSequential().

Reimplemented in QtCore.QProcess, QtNetwork.QSslSocket, QtNetwork.QLocalSocket, and QtNetwork.QAbstractSocket.

virtual long QtCore.QIODevice.BytesToWrite ( )

virtual

For buffered devices, this function returns the number of bytes waiting to be written. For devices with no buffer, this function returns 0.

See also bytesAvailable(), bytesWritten(), and isSequential().

Reimplemented in QtCore.QProcess, QtNetwork.QSslSocket, QtNetwork.QLocalSocket, and QtNetwork.QAbstractSocket.

virtual bool QtCore.QIODevice.CanReadLine ( )

virtual

Returns true if a complete line of data can be read from the device; otherwise returns false.

Note that unbuffered devices, which have no way of determining what can be read, always return false.

This function is often called in conjunction with the readyRead() signal.

Subclasses that reimplement this function must call the base implementation in order to include the contents of the QIODevice's buffer. Example:

bool CustomDevice::canReadLine() const

{

return buffer.contains('\n') || QIODevice::canReadLine();

}

See also openMode() and OpenMode.

new bool QtCore.QIODevice.IsReadable ( )

Returns true if data can be read from the device; otherwise returns false. Use bytesAvailable() to determine how many bytes can be read.

This is a convenience function which checks if the OpenMode of the device contains the ReadOnly flag.

See also openMode() and OpenMode.

virtual bool QtCore.QIODevice.IsSequential ( )

virtual

Returns true if this device is sequential; otherwise returns false.

Sequential devices, as opposed to a random-access devices, have no concept of a start, an end, a size, or a current position, and they do not support seeking. You can only read from the device when it reports that data is available. The most common example of a sequential device is a network socket. On Unix, special files such as /dev/zero and fifo pipes are sequential.

Regular files, on the other hand, do support random access. They have both a size and a current position, and they also support seeking backwards and forwards in the data stream. Regular files are non-sequential.

The QIODevice implementation returns false.

See also openMode() and OpenMode.

new void QtCore.QIODevice.OnAboutToClose ( )

protected

This signal is emitted when the device is about to close. Connect this signal if you have operations that need to be performed before the device closes (e.g., if you have data in a separate buffer that needs to be written to the device).

new void QtCore.QIODevice.OnBytesWritten ( long bytes )

protected

This signal is emitted every time a payload of data has been written to the device. The bytes argument is set to the number of bytes that were written in this payload.

bytesWritten() is not emitted recursively; if you reenter the event loop or call waitForBytesWritten() inside a slot connected to the bytesWritten() signal, the signal will not be reemitted (although waitForBytesWritten() may still return true).

See also openMode() and OpenMode.

Reimplemented in QtCore.QTemporaryFile, QtCore.QFile, and QtCore.QBuffer.

new QIODevice.OpenModeFlag QtCore.QIODevice.OpenMode ( )

Returns the mode in which the device has been opened; i.e. ReadOnly or WriteOnly.

See also openMode() and OpenMode.

new void QtCore.QIODevice.SetTextModeEnabled ( bool enabled )

If enabled is true, this function sets the Text flag on the device; otherwise the Text flag is removed. This feature is useful for classes that provide custom end-of-line handling on a QIODevice.

The IO device should be opened before calling this function.

See also isTextModeEnabled(), open(), and setOpenMode().

virtual long QtCore.QIODevice.Size ( )

virtual

For open random-access devices, this function returns the size of the device. For open sequential devices, bytesAvailable() is returned.

If the device is closed, the size returned will not reflect the actual size of the device.

Property Documentation

Slot QtCore.QIODevice.AboutToClose

addremove

This signal is emitted when the device is about to close. Connect this signal if you have operations that need to be performed before the device closes (e.g., if you have data in a separate buffer that needs to be written to the device).

Slot<System.Int64> QtCore.QIODevice.BytesWritten

addremove

This signal is emitted every time a payload of data has been written to the device. The bytes argument is set to the number of bytes that were written in this payload.

bytesWritten() is not emitted recursively; if you reenter the event loop or call waitForBytesWritten() inside a slot connected to the bytesWritten() signal, the signal will not be reemitted (although waitForBytesWritten() may still return true).

new long QtCore.QIODevice.Peek	(	Pointer< sbyte >	data,
		long	maxlen
	)

new long QtCore.QIODevice.Read	(	Pointer< sbyte >	data,
		long	maxlen
	)

new long QtCore.QIODevice.ReadLine	(	Pointer< sbyte >	data,
		long	maxlen
	)

new long QtCore.QIODevice.Write	(	string	data,
		long	len
	)

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Properties

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Property Documentation