The QLibrary class loads shared libraries at runtime. More...

Inheritance diagram for QtCore.QLibrary:

Collaboration diagram for QtCore.QLibrary:

Public Types
enum	LoadHint { ExportExternalSymbolsHint = 2, ImprovedSearchHeuristics = 8, LoadArchiveMemberHint = 4, ResolveAllSymbolsHint = 1 }
	More...

Public Member Functions
	QLibrary (QObject parent=null)


	QLibrary (string fileName, QObject parent=null)


	QLibrary (string fileName, int verNum, QObject parent=null)


	QLibrary (string fileName, string version, QObject parent=null)


override void	CreateProxy ()

new string	ErrorString ()


new bool	IsLoaded ()


new bool	Load ()


new QLibrary.LoadHint	loadHints ()

new void	SetFileNameAndVersion (string fileName, int verNum)


new void	SetFileNameAndVersion (string fileName, string version)


new void	SetLoadHints (QLibrary.LoadHint hints)

new bool	Unload ()


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 bool	IsLibrary (string fileName)


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
	QLibrary (System.Type dummy)

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
new string	FileName `[get, set]`


new LoadHint	LoadHints `[get, set]`


static new QMetaObject	StaticMetaObject `[get]`

new IQLibrarySignals	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 QLibrary class loads shared libraries at runtime.

An instance of a QLibrary object operates on a single shared object file (which we call a "library", but is also known as a "DLL"). A QLibrary provides access to the functionality in the library in a platform independent way. You can either pass a file name in the constructor, or set it explicitly with setFileName(). When loading the library, QLibrary searches in all the system-specific library locations (e.g. LD_LIBRARY_PATH on Unix), unless the file name has an absolute path. If the file cannot be found, QLibrary tries the name with different platform-specific file suffixes, like ".so" on Unix, ".dylib" on the Mac, or ".dll" on Windows and Symbian. This makes it possible to specify shared libraries that are only identified by their basename (i.e. without their suffix), so the same code will work on different operating systems.

The most important functions are load() to dynamically load the library file, isLoaded() to check whether loading was successful, and resolve() to resolve a symbol in the library. The resolve() function implicitly tries to load the library if it has not been loaded yet. Multiple instances of QLibrary can be used to access the same physical library. Once loaded, libraries remain in memory until the application terminates. You can attempt to unload a library using unload(), but if other instances of QLibrary are using the same library, the call will fail, and unloading will only happen when every instance has called unload().

A typical use of QLibrary is to resolve an exported symbol in a library, and to call the C function that this symbol represents. This is called "explicit linking" in contrast to "implicit linking", which is done by the link step in the build process when linking an executable against a library.

Note: In Symbian resolving symbols using their names is supported only if the library is built as STDDLL. Otherwise ordinals must be used. Also, in Symbian the path of the library is ignored and system default library location is always used.

The following code snippet loads a library, resolves the symbol "mysymbol", and calls the function if everything succeeded. If something goes wrong, e.g. the library file does not exist or the symbol is not defined, the function pointer will be 0 and won't be called.

QLibrary myLib("mylib");

typedef void (*MyPrototype)();

MyPrototype myFunction = (MyPrototype) myLib.resolve("mysymbol");

if (myFunction)

myFunction();

The symbol must be exported as a C function from the library for resolve() to work. This means that the function must be wrapped in an extern "C" block if the library is compiled with a C++ compiler. On Windows, this also requires the use of a dllexport macro; see resolve() for the details of how this is done. For convenience, there is a static resolve() function which you can use if you just want to call a function in a library without explicitly loading the library first:

typedef void (*MyPrototype)();

MyPrototype myFunction =

(MyPrototype) QLibrary::resolve("mylib", "mysymbol");

if (myFunction)

myFunction();

Member Enumeration Documentation

enum QtCore.QLibrary.LoadHint

This enum describes the possible hints that can be used to change the way libraries are handled when they are loaded. These values indicate how symbols are resolved when libraries are loaded, and are specified using the setLoadHints() function.

Constructor & Destructor Documentation

QtCore.QLibrary.QLibrary ( System.Type dummy )

protected

QtCore.QLibrary.QLibrary ( QObject parent = null )

Constructs a library with the given parent.

QtCore.QLibrary.QLibrary	(	string	fileName,
		QObject	parent = `null`
	)

Constructs a library object with the given parent that will load the library specified by fileName.

We recommend omitting the file's suffix in fileName, since QLibrary will automatically look for the file with the appropriate suffix in accordance with the platform, e.g. ".so" on Unix, ".dylib" on Mac OS X, and ".dll" on Windows. (See fileName.)

Note: In Symbian the path portion of the fileName is ignored.

QtCore.QLibrary.QLibrary	(	string	fileName,
		int	verNum,
		QObject	parent = `null`
	)

Constructs a library object with the given parent that will load the library specified by fileName and major version number verNum. Currently, the version number is ignored on Windows and Symbian.

We recommend omitting the file's suffix in fileName, since QLibrary will automatically look for the file with the appropriate suffix in accordance with the platform, e.g. ".so" on Unix, ".dylib" on Mac OS X, and ".dll" on Windows. (See fileName.)

Note: In Symbian the path portion of the fileName is ignored.

QtCore.QLibrary.QLibrary	(	string	fileName,
		string	version,
		QObject	parent = `null`
	)

Constructs a library object with the given parent that will load the library specified by fileName and full version number version. Currently, the version number is ignored on Windows and Symbian.

We recommend omitting the file's suffix in fileName, since QLibrary will automatically look for the file with the appropriate suffix in accordance with the platform, e.g. ".so" on Unix, ".dylib" on Mac OS X, and ".dll" on Windows. (See fileName.)

Note: In Symbian the path portion of the fileName is ignored.

Member Function Documentation

override void QtCore.QLibrary.CreateProxy ( )

virtual

Reimplemented from QtCore.QObject.

new void QtCore.QLibrary.Dispose ( )

new string QtCore.QLibrary.ErrorString ( )

Returns a text string with the description of the last error that occurred. Currently, errorString will only be set if load(), unload() or resolve() for some reason fails.

This function was introduced in Qt 4.2.

static bool QtCore.QLibrary.IsLibrary ( string fileName )

static

Returns true if fileName has a valid suffix for a loadable library; otherwise returns false.

PlatformValid suffixes

Windows .dll, .DLL

Unix/Linux .so

AIX .a

HP-UX .sl, .so (HP-UXi)

Mac OS X .dylib, .bundle, .so

Symbian .dll

Trailing versioning numbers on Unix are ignored.

new bool QtCore.QLibrary.IsLoaded ( )

Returns true if the library is loaded; otherwise returns false.

Property Documentation

new IQLibrarySignals QtCore.QLibrary.Emit

getprotected

new string QtCore.QLibrary.FileName

getset

This property holds the file name of the library.

We recommend omitting the file's suffix in the file name, since QLibrary will automatically look for the file with the appropriate suffix (see isLibrary()).

When loading the library, QLibrary searches in all system-specific library locations (e.g. LD_LIBRARY_PATH on Unix), unless the file name has an absolute path. After loading the library successfully, fileName() returns the fully-qualified file name of the library, including the full path to the library if one was given in the constructor or passed to setFileName().

For example, after successfully loading the "GL" library on Unix platforms, fileName() will return "libGL.so". If the file name was originally passed as "/usr/lib/libGL", fileName() will return "/usr/lib/libGL.so".

Note: In Symbian the path portion of the fileName is ignored.

new LoadHint QtCore.QLibrary.LoadHints

getset

This property holds give the load() function some hints on how it should behave.

You can give some hints on how the symbols are resolved. Usually, the symbols are not resolved at load time, but resolved lazily, (that is, when resolve() is called). If you set the loadHint to ResolveAllSymbolsHint, then all symbols will be resolved at load time if the platform supports it.

Setting ExportExternalSymbolsHint will make the external symbols in the library available for resolution in subsequent loaded libraries.

If LoadArchiveMemberHint is set, the file name is composed of two components: A path which is a reference to an archive file followed by the second component which is the reference to the archive member. For instance, the fileName libGL.a(shr_64.o) will refer to the library shr_64.o in the archive file named libGL.a. This is only supported on the AIX platform.

The interpretation of the load hints is platform dependent, and if you use it you are probably making some assumptions on which platform you are compiling for, so use them only if you understand the consequences of them.

By default, none of these flags are set, so libraries will be loaded with lazy symbol resolution, and will not export external symbols for resolution in other dynamically-loaded libraries.

new QMetaObject QtCore.QLibrary.StaticMetaObject

staticget

ExportExternalSymbolsHint	Exports unresolved and external symbols in the library so that they can be resolved in other dynamically-loaded libraries loaded later.
ImprovedSearchHeuristics
LoadArchiveMemberHint	Allows the file name of the library to specify a particular object file within an archive file. If this hint is given, the filename of the library consists of a path, which is a reference to an archive file, followed by a reference to the archive member.
ResolveAllSymbolsHint	Causes all symbols in a library to be resolved when it is loaded, not simply when resolve() is called.

new void QtCore.QLibrary.SetFileNameAndVersion	(	string	fileName,
		int	verNum
	)

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