QtCore.QSocketNotifier Class Reference

The QSocketNotifier class provides support for monitoring activity on a file descriptor. More...

Inheritance diagram for QtCore.QSocketNotifier:

Collaboration diagram for QtCore.QSocketNotifier:

Public Types
enum	Type { Exception = 2, Read = 0, Write = 1 }
	More...

Public Member Functions
	QSocketNotifier (int socket, QSocketNotifier.Type arg2, QObject parent=null)
override void	CreateProxy ()
override bool	OnEvent (QEvent arg1)
new bool	IsEnabled ()
new void	SetEnabled (bool arg1)
new int	Socket ()
new QSocketNotifier.Type	type ()
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	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
	QSocketNotifier (System.Type dummy)
new void	OnActivated (int socket)
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< System.Int32 >	Activated
static new QMetaObject	StaticMetaObject [get]
new IQSocketNotifierSignals	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 QSocketNotifier class provides support for monitoring activity on a file descriptor.

The QSocketNotifier makes it possible to integrate Qt's event loop with other event loops based on file descriptors. For example, the CORBA Framework uses it to process CORBA events. File descriptor action is detected in Qt's main event loop (QCoreApplication::exec()).

Once you have opened a device using a low-level (usually platform-specific) API, you can create a socket notifier to monitor the file descriptor. The socket notifier is enabled by default, i.e. it emits the activated() signal whenever a socket event corresponding to its type occurs. Connect the activated() signal to the slot you want to be called when an event corresponding to your socket notifier's type occurs.

There are three types of socket notifiers: read, write, and exception. The type is described by the Type enum, and must be specified when constructing the socket notifier. After construction it can be determined using the type() function. Note that if you need to monitor both reads and writes for the same file descriptor, you must create two socket notifiers. Note also that it is not possible to install two socket notifiers of the same type (Read, Write, Exception) on the same socket.

The setEnabled() function allows you to disable as well as enable the socket notifier. It is generally advisable to explicitly enable or disable the socket notifier, especially for write notifiers. A disabled notifier ignores socket events (the same effect as not creating the socket notifier). Use the isEnabled() function to determine the notifier's current status.

Finally, you can use the socket() function to retrieve the socket identifier. Although the class is called QSocketNotifier, it is normally used for other types of devices than sockets. QTcpSocket and QUdpSocket provide notification through signals, so there is normally no need to use a QSocketNotifier on them.

Notes for Windows Users

The socket passed to QSocketNotifier will become non-blocking, even if it was created as a blocking socket. The activated() signal is sometimes triggered by high general activity on the host, even if there is nothing to read. A subsequent read from the socket can then fail, the error indicating that there is no data available (e.g., WSAEWOULDBLOCK). This is an operating system limitation, and not a bug in QSocketNotifier.

To ensure that the socket notifier handles read notifications correctly, follow these steps when you receive a notification:

Disable the notifier.

Read data from the socket.

Re-enable the notifier if you are interested in more data (such as after having written a new command to a remote server).

To ensure that the socket notifier handles write notifications correctly, follow these steps when you receive a notification:

Disable the notifier.

Write as much data as you can (before EWOULDBLOCK is returned).

Re-enable notifier if you have more data to write.

Further information: On Windows, Qt always disables the notifier after getting a notification, and only re-enables it if more data is expected. For example, if data is read from the socket and it can be used to read more, or if reading or writing is not possible because the socket would block, in which case it is necessary to wait before attempting to read or write again.

See also QFile, QProcess, QTcpSocket, and QUdpSocket.

Member Enumeration Documentation

enum QtCore.QSocketNotifier.Type

This enum describes the various types of events that a socket notifier can recognize. The type must be specified when constructing the socket notifier.

Note that if you need to monitor both reads and writes for the same file descriptor, you must create two socket notifiers. Note also that it is not possible to install two socket notifiers of the same type (Read, Write, Exception) on the same socket.

See also QSocketNotifier() and type().

Enumerator:

Exception	An exception has occurred. We recommend against using this.
Read	There is data to be read.
Write	Data can be written.

Constructor & Destructor Documentation

QtCore.QSocketNotifier.QSocketNotifier ( System.Type  dummy )

protected

QtCore.QSocketNotifier.QSocketNotifier	(	int	socket,
		QSocketNotifier.Type	arg2,
		QObject	parent = null
	)

Constructs a socket notifier with the given parent. It enables the socket, and watches for events of the given type.

It is generally advisable to explicitly enable or disable the socket notifier, especially for write notifiers.

Note for Windows users: The socket passed to QSocketNotifier will become non-blocking, even if it was created as a blocking socket.

See also setEnabled() and isEnabled().

Member Function Documentation

override void QtCore.QSocketNotifier.CreateProxy ( )

virtual

Reimplemented from QtCore.QObject.

new void QtCore.QSocketNotifier.Dispose

(

)

new bool QtCore.QSocketNotifier.IsEnabled

(

)

Returns true if the notifier is enabled; otherwise returns false.

See also setEnabled().

new void QtCore.QSocketNotifier.OnActivated ( int  socket )

protected

This signal is emitted whenever the socket notifier is enabled and a socket event corresponding to its type occurs.

The socket identifier is passed in the socket parameter.

See also type() and socket().

override bool QtCore.QSocketNotifier.OnEvent ( QEvent  arg1 )

virtual

Reimplemented from QObject::event().

Reimplemented from QtCore.QObject.

new void QtCore.QSocketNotifier.SetEnabled

(

bool

arg1

)

If enable is true, the notifier is enabled; otherwise the notifier is disabled.

The notifier is enabled by default, i.e. it emits the activated() signal whenever a socket event corresponding to its type occurs. If it is disabled, it ignores socket events (the same effect as not creating the socket notifier).

Write notifiers should normally be disabled immediately after the activated() signal has been emitted

See also isEnabled() and activated().

new int QtCore.QSocketNotifier.Socket

(

)

Returns the socket identifier specified to the constructor.

See also type().

static string QtCore.QSocketNotifier.Tr ( string  s, string  c = null  )

static

static string QtCore.QSocketNotifier.Tr ( string  s, string  c, int  n  )

static

static string QtCore.QSocketNotifier.TrUtf8 ( string  s, string  c = null  )

static

static string QtCore.QSocketNotifier.TrUtf8 ( string  s, string  c, int  n  )

static

new QSocketNotifier.Type QtCore.QSocketNotifier.type

(

)

Returns the socket event type specified to the constructor.

See also socket().

Property Documentation

Slot<System.Int32> QtCore.QSocketNotifier.Activated

addremove

This signal is emitted whenever the socket notifier is enabled and a socket event corresponding to its type occurs.

The socket identifier is passed in the socket parameter.

See also type() and socket().

new IQSocketNotifierSignals QtCore.QSocketNotifier.Emit

getprotected

new QMetaObject QtCore.QSocketNotifier.StaticMetaObject

staticget