QTemporaryFile Class Reference

\inmodule QtCore \reentrant More...

#include <qtemporaryfile.h>

Inheritance diagram for QTemporaryFile:

Collaboration diagram for QTemporaryFile:

Public Member Functions
	QTemporaryFile ()
	Constructs a QTemporaryFile using as file template the application name returned by QCoreApplication::applicationName() (otherwise qt_temp) followed by ".XXXXXX".
	QTemporaryFile (const QString &templateName)
	Constructs a QTemporaryFile with a template filename of templateName.
	QTemporaryFile (QObject *parent)
	Constructs a QTemporaryFile (with the given parent) using as file template the application name returned by QCoreApplication::applicationName() (otherwise qt_temp) followed by ".XXXXXX".
	QTemporaryFile (const QString &templateName, QObject *parent)
	Constructs a QTemporaryFile with a template filename of templateName and the specified parent.
	~QTemporaryFile ()
	Destroys the temporary file object, the file is automatically closed if necessary and if in auto remove mode it will automatically delete the file.
bool	autoRemove () const
	Returns true if the QTemporaryFile is in auto remove mode.
void	setAutoRemove (bool b)
	Sets the QTemporaryFile into auto-remove mode if b is true.
bool	open ()
	A QTemporaryFile will always be opened in QIODevice::ReadWrite mode, this allows easy access to the data in the file.
QString	fileName () const override
	Returns the complete unique filename backing the QTemporaryFile object.
QString	fileTemplate () const
	Returns the set file template.
void	setFileTemplate (const QString &name)
	Sets the static portion of the file name to name.
bool	rename (const QString &newName)
	Renames the current temporary file to newName and returns true if it succeeded.
Public Member Functions inherited from QFile
	QFile ()
	Constructs a QFile object.
QFILE_MAYBE_EXPLICIT	QFile (const QString &name)
	QFile (QObject *parent)
	Constructs a new file object with the given parent.
	QFile (const QString &name, QObject *parent)
	Constructs a new file object with the given parent to represent the file with the specified name.
	~QFile ()
	Destroys the file object, closing it if necessary.
QString	fileName () const override
	Returns the name set by setFileName() or to the QFile constructors.
void	setFileName (const QString &name)
	Sets the name of the file.
bool	exists () const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns true if the file specified by fileName() exists; otherwise returns false.
QString	symLinkTarget () const
bool	remove ()
	Removes the file specified by fileName().
bool	moveToTrash ()
bool	rename (const QString &newName)
	Renames the file currently specified by fileName() to newName.
bool	link (const QString &newName)
	Creates a link named linkName that points to the file currently specified by fileName().
bool	copy (const QString &newName)
	Copies the file named fileName() to newName.
bool	open (OpenMode flags) override
	Opens the file using OpenMode mode, returning true if successful; otherwise false.
bool	open (OpenMode flags, Permissions permissions)
bool	open (FILE *f, OpenMode ioFlags, FileHandleFlags handleFlags=DontCloseHandle)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Opens the existing file handle fh in the given mode.
bool	open (int fd, OpenMode ioFlags, FileHandleFlags handleFlags=DontCloseHandle)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Opens the existing file descriptor fd in the given mode.
qint64	size () const override
	\reimp
bool	resize (qint64 sz) override
	\reimp
Permissions	permissions () const override
	\reimp
bool	setPermissions (Permissions permissionSpec) override
	Sets the permissions for the file to the permissions specified.
Public Member Functions inherited from QFileDevice
	~QFileDevice ()
	Destroys the file device, closing it if necessary.
FileError	error () const
	Returns the file error status.
void	unsetError ()
	Sets the file's error to QFileDevice::NoError.
void	close () override
	Calls QFileDevice::flush() and closes the file.
bool	isSequential () const override
	Returns true if the file can only be manipulated sequentially; otherwise returns false.
int	handle () const
	Returns the file handle of the file.
virtual QString	fileName () const
	Returns the name of the file.
qint64	pos () const override
	\reimp
bool	seek (qint64 offset) override
	For random-access devices, this function sets the current position to pos, returning true on success, or false if an error occurred.
bool	atEnd () const override
	Returns true if the end of the file has been reached; otherwise returns false.
bool	flush ()
	Flushes any buffered data to the file.
qint64	size () const override
	Returns the size of the file.
virtual bool	resize (qint64 sz)
	Sets the file size (in bytes) sz.
virtual Permissions	permissions () const
	Returns the complete OR-ed together combination of QFile::Permission for the file.
virtual bool	setPermissions (Permissions permissionSpec)
	Sets the permissions for the file to the permissions specified.
uchar *	map (qint64 offset, qint64 size, MemoryMapFlags flags=NoOptions)
	Maps size bytes of the file into memory starting at offset.
bool	unmap (uchar *address)
	Unmaps the memory address.
QDateTime	fileTime (QFileDevice::FileTime time) const
bool	setFileTime (const QDateTime &newDate, QFileDevice::FileTime fileTime)
Public Member Functions inherited from QIODevice
	QIODevice ()
	Constructs a QIODevice object.
	QIODevice (QObject *parent)
	Constructs a QIODevice object with the given parent.
virtual	~QIODevice ()
	The destructor is virtual, and QIODevice is an abstract base class.
QIODeviceBase::OpenMode	openMode () const
	Returns the mode in which the device has been opened; i.e.
void	setTextModeEnabled (bool enabled)
	If enabled is true, this function sets the \l Text flag on the device; otherwise the \l Text flag is removed.
bool	isTextModeEnabled () const
	Returns true if the \l Text flag is enabled; otherwise returns false.
bool	isOpen () const
	Returns true if the device is open; otherwise returns false.
bool	isReadable () const
	Returns true if data can be read from the device; otherwise returns false.
bool	isWritable () const
	Returns true if data can be written to the device; otherwise returns false.
virtual bool	isSequential () const
	Returns true if this device is sequential; otherwise returns false.
int	readChannelCount () const
int	writeChannelCount () const
int	currentReadChannel () const
void	setCurrentReadChannel (int channel)
int	currentWriteChannel () const
void	setCurrentWriteChannel (int channel)
virtual bool	open (QIODeviceBase::OpenMode mode)
	Opens the device and sets its OpenMode to mode.
virtual void	close ()
	First emits aboutToClose(), then closes the device and sets its OpenMode to NotOpen.
virtual qint64	pos () const
	For random-access devices, this function returns the position that data is written to or read from.
virtual qint64	size () const
	For open random-access devices, this function returns the size of the device.
virtual bool	seek (qint64 pos)
	For random-access devices, this function sets the current position to pos, returning true on success, or false if an error occurred.
virtual bool	atEnd () const
	Returns true if the current read and write position is at the end of the device (i.e.
virtual bool	reset ()
	Seeks to the start of input for random-access devices.
virtual qint64	bytesAvailable () const
	Returns the number of bytes that are available for reading.
virtual qint64	bytesToWrite () const
	For buffered devices, this function returns the number of bytes waiting to be written.
qint64	read (char *data, qint64 maxlen)
	Reads at most maxSize bytes from the device into data, and returns the number of bytes read.
QByteArray	read (qint64 maxlen)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Reads at most maxSize bytes from the device, and returns the data read as a QByteArray.
QByteArray	readAll ()
	Reads all remaining data from the device, and returns it as a byte array.
qint64	readLine (char *data, qint64 maxlen)
	This function reads a line of ASCII characters from the device, up to a maximum of maxSize - 1 bytes, stores the characters in data, and returns the number of bytes read.
QByteArray	readLine (qint64 maxlen=0)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Reads a line from the device, but no more than maxSize characters, and returns the result as a byte array.
virtual bool	canReadLine () const
	Returns true if a complete line of data can be read from the device; otherwise returns false.
void	startTransaction ()
void	commitTransaction ()
void	rollbackTransaction ()
bool	isTransactionStarted () const
qint64	write (const char *data, qint64 len)
	Writes at most maxSize bytes of data from data to the device.
qint64	write (const char *data)
qint64	write (const QByteArray &data)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Writes the content of data to the device.
qint64	peek (char *data, qint64 maxlen)
QByteArray	peek (qint64 maxlen)
qint64	skip (qint64 maxSize)
virtual bool	waitForReadyRead (int msecs)
	Blocks until new data is available for reading and the readyRead() signal has been emitted, or until msecs milliseconds have passed.
virtual bool	waitForBytesWritten (int msecs)
	For buffered devices, this function waits until a payload of buffered written data has been written to the device and the bytesWritten() signal has been emitted, or until msecs milliseconds have passed.
void	ungetChar (char c)
	Puts the character c back into the device, and decrements the current position unless the position is 0.
bool	putChar (char c)
	Writes the character c to the device.
bool	getChar (char *c)
	Reads one character from the device and stores it in c.
QString	errorString () const
	Returns a human-readable description of the last device error that occurred.
Public Member Functions inherited from QObject
Q_INVOKABLE	QObject (QObject *parent=nullptr)
	Constructs an object with parent object parent.
virtual	~QObject ()
	Destroys the object, deleting all its child objects.
virtual bool	event (QEvent *event)
	This virtual function receives events to an object and should return true if the event e was recognized and processed.
virtual bool	eventFilter (QObject *watched, QEvent *event)
	Filters events if this object has been installed as an event filter for the watched object.
QString	objectName () const
Q_WEAK_OVERLOAD void	setObjectName (const QString &name)
	Sets the object's name to name.
void	setObjectName (QAnyStringView name)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
QBindable< QString >	bindableObjectName ()
bool	isWidgetType () const
	Returns true if the object is a widget; otherwise returns false.
bool	isWindowType () const
	Returns true if the object is a window; otherwise returns false.
bool	isQuickItemType () const
	Returns true if the object is a QQuickItem; otherwise returns false.
bool	signalsBlocked () const noexcept
	Returns true if signals are blocked; otherwise returns false.
bool	blockSignals (bool b) noexcept
	If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it).
QThread *	thread () const
	Returns the thread in which the object lives.
void	moveToThread (QThread *thread)
	Changes the thread affinity for this object and its children.
int	startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)
	This is an overloaded function that will start a timer of type timerType and a timeout of interval milliseconds.
int	startTimer (std::chrono::milliseconds time, Qt::TimerType timerType=Qt::CoarseTimer)
void	killTimer (int id)
	Kills the timer with timer identifier, id.
template<typename T >
T	findChild (const QString &aName=QString(), Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	Returns the child of this object that can be cast into type T and that is called name, or \nullptr if there is no such object.
template<typename T >
QList< T >	findChildren (const QString &aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects.
template<typename T >
QList< T >	findChildren (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
const QObjectList &	children () const
	Returns a list of child objects.
void	setParent (QObject *parent)
	Makes the object a child of parent.
void	installEventFilter (QObject *filterObj)
	Installs an event filter filterObj on this object.
void	removeEventFilter (QObject *obj)
	Removes an event filter object obj from this object.
QMetaObject::Connection	connect (const QObject *sender, const char *signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const
bool	disconnect (const char *signal=nullptr, const QObject *receiver=nullptr, const char *member=nullptr) const
bool	disconnect (const QObject *receiver, const char *member=nullptr) const
void	dumpObjectTree () const
	Dumps a tree of children to the debug output.
void	dumpObjectInfo () const
	Dumps information about signal connections, etc.
bool	setProperty (const char *name, const QVariant &value)
	Sets the value of the object's name property to value.
bool	setProperty (const char *name, QVariant &&value)
QVariant	property (const char *name) const
	Returns the value of the object's name property.
QList< QByteArray >	dynamicPropertyNames () const
QBindingStorage *	bindingStorage ()
const QBindingStorage *	bindingStorage () const
QObject *	parent () const
	Returns a pointer to the parent object.
bool	inherits (const char *classname) const
	Returns true if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false.

Static Public Member Functions
static QTemporaryFile *	createNativeFile (const QString &fileName)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Works on the given fileName rather than an existing QFile object.
static QTemporaryFile *	createNativeFile (QFile &file)
	If file is not already a native file, then a QTemporaryFile is created in QDir::tempPath(), the contents of file is copied into it, and a pointer to the temporary file is returned.
Static Public Member Functions inherited from QFile
static QByteArray	encodeName (const QString &fileName)
	Converts fileName to an 8-bit encoding that you can use in native APIs.
static QString	decodeName (const QByteArray &localFileName)
	This does the reverse of QFile::encodeName() using localFileName.
static QString	decodeName (const char *localFileName)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns the Unicode version of the given localFileName.
static bool	exists (const QString &fileName)
	Returns true if the file specified by fileName exists; otherwise returns false.
static QString	symLinkTarget (const QString &fileName)
static bool	remove (const QString &fileName)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Removes the file specified by the fileName given.
static bool	moveToTrash (const QString &fileName, QString *pathInTrash=nullptr)
static bool	rename (const QString &oldName, const QString &newName)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Renames the file oldName to newName.
static bool	link (const QString &fileName, const QString &newName)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Creates a link named linkName that points to the file fileName.
static bool	copy (const QString &fileName, const QString &newName)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Copies the file named fileName to newName.
static bool	resize (const QString &filename, qint64 sz)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Sets fileName to size (in bytes) sz.
static Permissions	permissions (const QString &filename)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns the complete OR-ed together combination of QFile::Permission for fileName.
static bool	setPermissions (const QString &filename, Permissions permissionSpec)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Sets the permissions for fileName file to permissions.
Static Public Member Functions inherited from QObject
static QMetaObject::Connection	connect (const QObject *sender, const char *signal, const QObject *receiver, const char *member, Qt::ConnectionType=Qt::AutoConnection)
	\threadsafe
static QMetaObject::Connection	connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)
template<typename Func1 , typename Func2 >
static QMetaObject::Connection	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const typename QtPrivate::ContextTypeForFunctor< Func2 >::ContextType *context, Func2 &&slot, Qt::ConnectionType type=Qt::AutoConnection)
template<typename Func1 , typename Func2 >
static QMetaObject::Connection	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, Func2 &&slot)
static bool	disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *member)
	\threadsafe
static bool	disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &member)
static bool	disconnect (const QMetaObject::Connection &)
	Disconnect a connection.
template<typename Func1 , typename Func2 >
static bool	disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const typename QtPrivate::FunctionPointer< Func2 >::Object *receiver, Func2 slot)
template<typename Func1 >
static bool	disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const QObject *receiver, void **zero)

Protected Member Functions
bool	open (OpenMode flags) override
	\reimp
Protected Member Functions inherited from QFile
	QFile (QFilePrivate &dd, QObject *parent=nullptr)
Protected Member Functions inherited from QFileDevice
	QFileDevice ()
	QFileDevice (QObject *parent)
	QFileDevice (QFileDevicePrivate &dd, QObject *parent=nullptr)
qint64	readData (char *data, qint64 maxlen) override
	\reimp
qint64	writeData (const char *data, qint64 len) override
	\reimp
qint64	readLineData (char *data, qint64 maxlen) override
	\reimp
Protected Member Functions inherited from QIODevice
	QIODevice (QIODevicePrivate &dd, QObject *parent=nullptr)
virtual qint64	readData (char *data, qint64 maxlen)=0
	Reads up to maxSize bytes from the device into data, and returns the number of bytes read or -1 if an error occurred.
virtual qint64	readLineData (char *data, qint64 maxlen)
	Reads up to maxSize characters into data and returns the number of characters read.
virtual qint64	skipData (qint64 maxSize)
virtual qint64	writeData (const char *data, qint64 len)=0
	Writes up to maxSize bytes from data to the device.
void	setOpenMode (QIODeviceBase::OpenMode openMode)
	Sets the OpenMode of the device to openMode.
void	setErrorString (const QString &errorString)
	Sets the human readable description of the last device error that occurred to str.
Protected Member Functions inherited from QObject
QObject *	sender () const
	Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns \nullptr.
int	senderSignalIndex () const
int	receivers (const char *signal) const
	Returns the number of receivers connected to the signal.
bool	isSignalConnected (const QMetaMethod &signal) const
virtual void	timerEvent (QTimerEvent *event)
	This event handler can be reimplemented in a subclass to receive timer events for the object.
virtual void	childEvent (QChildEvent *event)
	This event handler can be reimplemented in a subclass to receive child events.
virtual void	customEvent (QEvent *event)
	This event handler can be reimplemented in a subclass to receive custom events.
virtual void	connectNotify (const QMetaMethod &signal)
virtual void	disconnectNotify (const QMetaMethod &signal)
	QObject (QObjectPrivate &dd, QObject *parent=nullptr)
Protected Member Functions inherited from QIODeviceBase
	~QIODeviceBase ()=default

Friends
class	QFile
class	QLockFilePrivate

Additional Inherited Members
Public Types inherited from QFileDevice
enum	FileError {   NoError = 0 , ReadError = 1 , WriteError = 2 , FatalError = 3 ,   ResourceError = 4 , OpenError = 5 , AbortError = 6 , TimeOutError = 7 ,   UnspecifiedError = 8 , RemoveError = 9 , RenameError = 10 , PositionError = 11 ,   ResizeError = 12 , PermissionsError = 13 , CopyError = 14 }
	This enum describes the errors that may be returned by the error() function. More...
enum	FileTime { FileAccessTime , FileBirthTime , FileMetadataChangeTime , FileModificationTime }
enum	Permission {   ReadOwner = 0x4000 , WriteOwner = 0x2000 , ExeOwner = 0x1000 , ReadUser = 0x0400 ,   WriteUser = 0x0200 , ExeUser = 0x0100 , ReadGroup = 0x0040 , WriteGroup = 0x0020 ,   ExeGroup = 0x0010 , ReadOther = 0x0004 , WriteOther = 0x0002 , ExeOther = 0x0001 }
	This enum is used by the permission() function to report the permissions and ownership of a file. More...
enum	FileHandleFlag { AutoCloseHandle = 0x0001 , DontCloseHandle = 0 }
	This enum is used when opening a file to specify additional options which only apply to files and not to a generic QIODevice. More...
enum	MemoryMapFlag { NoOptions = 0 , MapPrivateOption = 0x0001 }
Public Types inherited from QIODeviceBase
enum	OpenModeFlag {   NotOpen = 0x0000 , ReadOnly = 0x0001 , WriteOnly = 0x0002 , ReadWrite = ReadOnly | WriteOnly ,   Append = 0x0004 , Truncate = 0x0008 , Text = 0x0010 , Unbuffered = 0x0020 ,   NewOnly = 0x0040 , ExistingOnly = 0x0080 }
	This enum is used with QIODevice::open() to describe the mode in which a device is opened. More...
Public Slots inherited from QObject
void	deleteLater ()
	\threadsafe
Signals inherited from QIODevice
void	readyRead ()
	This signal is emitted once every time new data is available for reading from the device's current read channel.
void	channelReadyRead (int channel)
void	bytesWritten (qint64 bytes)
	This signal is emitted every time a payload of data has been written to the device's current write channel.
void	channelBytesWritten (int channel, qint64 bytes)
void	aboutToClose ()
	This signal is emitted when the device is about to close.
void	readChannelFinished ()
Signals inherited from QObject
void	destroyed (QObject *=nullptr)
	This signal is emitted immediately before the object obj is destroyed, after any instances of QPointer have been notified, and cannot be blocked.
void	objectNameChanged (const QString &objectName, QPrivateSignal)
	This signal is emitted after the object's name has been changed.
Protected Attributes inherited from QObject
QScopedPointer< QObjectData >	d_ptr
Properties inherited from QObject
QString	objectName
	the name of this object
Related Symbols inherited from QObject
template< class T > T	qobject_cast (const QObject *object)
	Returns the given object cast to type T if the object is of type T (or of a subclass); otherwise returns \nullptr.
template< typename T > T	qFindChildqFindChildren (const QObject *obj, const QString &name)()
template< typename T > QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QString &name)()
	QObjectList
	\macro Q_CLASSINFO(Name, Value)

Detailed Description

\inmodule QtCore \reentrant

The QTemporaryFile class is an I/O device that operates on temporary files.

QTemporaryFile is used to create unique temporary files safely. The file itself is created by calling open(). The name of the temporary file is guaranteed to be unique (i.e., you are guaranteed to not overwrite an existing file), and the file will subsequently be removed upon destruction of the QTemporaryFile object. This is an important technique that avoids data corruption for applications that store data in temporary files. The file name is either auto-generated, or created based on a template, which is passed to QTemporaryFile's constructor.

Example:

    // Within a function/method...
 
    QTemporaryFile file;
    if (file.open()) {
        // file.fileName() returns the unique file name
    }
 
    // The QTemporaryFile destructor removes the temporary file
    // as it goes out of scope.

Reopening a QTemporaryFile after calling close() is safe. For as long as the QTemporaryFile object itself is not destroyed, the unique temporary file will exist and be kept open internally by QTemporaryFile.

The file name of the temporary file can be found by calling fileName(). Note that this is only defined after the file is first opened; the function returns an empty string before this.

A temporary file will have some static part of the name and some part that is calculated to be unique. The default filename will be determined from QCoreApplication::applicationName() (otherwise qt_temp) and will be placed into the temporary path as returned by QDir::tempPath(). If you specify your own filename, a relative file path will not be placed in the temporary directory by default, but be relative to the current working directory. It is important to specify the correct directory if the rename() function will be called, as QTemporaryFile can only rename files within the same volume / filesystem as the temporary file itself was created on.

Specified filenames can contain the following template XXXXXX (six upper case "X" characters), which will be replaced by the auto-generated portion of the filename. Note that the template is case sensitive. If the template is not present in the filename, QTemporaryFile appends the generated part to the filename given.

Note

On Linux, QTemporaryFile will attempt to create unnamed temporary files. If that succeeds, open() will return true but exists() will be false. If you call fileName() or any function that calls it, QTemporaryFile will give the file a name, so most applications will not see a difference.

See also

QDir::tempPath(), QFile

Definition at line 22 of file qtemporaryfile.h.

Constructor & Destructor Documentation

QTemporaryFile() [1/4]

QTemporaryFile::QTemporaryFile

(

)

Constructs a QTemporaryFile using as file template the application name returned by QCoreApplication::applicationName() (otherwise qt_temp) followed by ".XXXXXX".

The file is stored in the system's temporary directory, QDir::tempPath().

See also

setFileTemplate(), QDir::tempPath()

Definition at line 628 of file qtemporaryfile.cpp.

Referenced by createNativeFile().

Here is the caller graph for this function:

QTemporaryFile() [2/4]

QTemporaryFile::QTemporaryFile ( const QString &  templateName )

explicit

Constructs a QTemporaryFile with a template filename of templateName.

Upon opening the temporary file this will be used to create a unique filename.

If the templateName does not contain XXXXXX it will automatically be appended and used as the dynamic portion of the filename.

If templateName is a relative path, the path will be relative to the current working directory. You can use QDir::tempPath() to construct templateName if you want use the system's temporary directory. It is important to specify the correct directory if the rename() function will be called, as QTemporaryFile can only rename files within the same volume / filesystem as the temporary file itself was created on.

See also

open(), fileTemplate()

Definition at line 651 of file qtemporaryfile.cpp.

QTemporaryFile() [3/4]

QTemporaryFile::QTemporaryFile ( QObject *  parent )

explicit

Constructs a QTemporaryFile (with the given parent) using as file template the application name returned by QCoreApplication::applicationName() (otherwise qt_temp) followed by ".XXXXXX".

The file is stored in the system's temporary directory, QDir::tempPath().

See also

setFileTemplate()

Definition at line 664 of file qtemporaryfile.cpp.

QTemporaryFile() [4/4]

QTemporaryFile::QTemporaryFile	(	const QString &	templateName,
		QObject *	parent
	)

Constructs a QTemporaryFile with a template filename of templateName and the specified parent.

Upon opening the temporary file this will be used to create a unique filename.

If the templateName does not contain XXXXXX it will automatically be appended and used as the dynamic portion of the filename.

If templateName is a relative path, the path will be relative to the current working directory. You can use QDir::tempPath() to construct templateName if you want use the system's temporary directory. It is important to specify the correct directory if the rename() function will be called, as QTemporaryFile can only rename files within the same volume / filesystem as the temporary file itself was created on.

See also

open(), fileTemplate()

Definition at line 687 of file qtemporaryfile.cpp.

~QTemporaryFile()

QTemporaryFile::~QTemporaryFile

(

)

Destroys the temporary file object, the file is automatically closed if necessary and if in auto remove mode it will automatically delete the file.

See also

autoRemove()

Definition at line 700 of file qtemporaryfile.cpp.

References QFileDevice::close(), d, and QFile::remove().

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Member Function Documentation

autoRemove()

bool QTemporaryFile::autoRemove

(

)

const

Returns true if the QTemporaryFile is in auto remove mode.

Auto-remove mode will automatically delete the filename from disk upon destruction. This makes it very easy to create your QTemporaryFile object on the stack, fill it with data, read from it, and finally on function return it will automatically clean up after itself.

Auto-remove is on by default.

See also

setAutoRemove(), remove()

Definition at line 731 of file qtemporaryfile.cpp.

References d.

createNativeFile() [1/2]

QTemporaryFile * QTemporaryFile::createNativeFile ( const QString &  fileName )

inlinestatic

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Works on the given fileName rather than an existing QFile object.

Definition at line 51 of file qtemporaryfile.h.

References file, and fileName.

Referenced by QMediaPlayerPrivate::setMedia().

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createNativeFile() [2/2]

QTemporaryFile * QTemporaryFile::createNativeFile ( QFile &  file )

static

If file is not already a native file, then a QTemporaryFile is created in QDir::tempPath(), the contents of file is copied into it, and a pointer to the temporary file is returned.

Does nothing and returns 0 if file is already a native file.

For example:

  QFile f(":/resources/file.txt");
  QTemporaryFile::createNativeFile(f); // Returns a pointer to a temporary file
 
  QFile f("/users/qt/file.txt");
  QTemporaryFile::createNativeFile(f); // Returns 0

See also

QFileInfo::isNativePath()

Definition at line 878 of file qtemporaryfile.cpp.

References QTemporaryFile(), QFileDevice::close(), engine, file, QAbstractFileEngine::FlagsMask, QIODevice::isOpen(), QAbstractFileEngine::LocalDiskFlag, QFile::open(), QFileDevice::pos(), QIODevice::read(), QIODeviceBase::ReadOnly, ret, and QFileDevice::seek().

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fileName()

QString QTemporaryFile::fileName ( ) const

overridevirtual

Returns the complete unique filename backing the QTemporaryFile object.

This string is null before the QTemporaryFile is opened, afterwards it will contain the fileTemplate() plus additional characters to make it unique.

See also

fileTemplate()

Reimplemented from QFile.

Definition at line 770 of file qtemporaryfile.cpp.

References d, QAbstractFileEngine::DefaultName, and QTemporaryFilePrivate::materializeUnnamedFile().

Referenced by createTemporaryItemCopy(), QRhiMetal::pipelineCacheData(), QRhiMetal::setPipelineCacheData(), QDBusTrayIcon::showMessage(), and QDBusTrayIcon::updateIcon().

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fileTemplate()

QString QTemporaryFile::fileTemplate

(

)

const

Returns the set file template.

The default file template will be called qcoreappname.XXXXXX and be placed in QDir::tempPath().

See also

setFileTemplate()

Definition at line 788 of file qtemporaryfile.cpp.

References d.

open() [1/2]

bool QTemporaryFile::open ( )

inline

A QTemporaryFile will always be opened in QIODevice::ReadWrite mode, this allows easy access to the data in the file.

This function will return true upon success and will set the fileName() to the unique filename used.

See also

fileName()

Definition at line 42 of file qtemporaryfile.h.

References open(), and QIODeviceBase::ReadWrite.

Referenced by createTemporaryItemCopy(), open(), QRhiMetal::pipelineCacheData(), and QRhiMetal::setPipelineCacheData().

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open() [2/2]

bool QTemporaryFile::open ( OpenMode  flags )

overrideprotected

\reimp

Creates a unique file name for the temporary file, and opens it. You can get the unique name later by calling fileName(). The file is guaranteed to have been created by this function (i.e., it has never existed before).

Definition at line 924 of file qtemporaryfile.cpp.

References d, QAbstractFileEngine::DefaultName, QFile::open(), and QIODevice::setOpenMode().

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rename()

bool QTemporaryFile::rename

(

const QString &

newName

)

Renames the current temporary file to newName and returns true if it succeeded.

This function has an important difference compared to QFile::rename(): it will not perform a copy+delete if the low-level system call to rename the file fails, something that could happen if newName specifies a file in a different volume or filesystem than the temporary file was created on. In other words, QTemporaryFile only supports atomic file renaming.

This functionality is intended to support materializing the destination file with all contents already present, so another process cannot see an incomplete file in the process of being written. The \l QSaveFile class can be used for a similar purpose too, particularly if the destination file is not temporary.

See also

QSaveFile, QSaveFile::commit(), QFile::rename()

Definition at line 833 of file qtemporaryfile.cpp.

References QFileDevice::close(), d, QFileDevice::error(), QFileDevice::NoError, QFile::rename(), QFileDevice::RenameError, and QFileDevice::unsetError().

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setAutoRemove()

void QTemporaryFile::setAutoRemove

(

bool

b

)

Sets the QTemporaryFile into auto-remove mode if b is true.

Auto-remove is on by default.

If you set this property to false, ensure the application provides a way to remove the file once it is no longer needed, including passing the responsibility on to another process. Always use the fileName() function to obtain the name and never try to guess the name that QTemporaryFile has generated.

On some systems, if fileName() is not called before closing the file, the temporary file may be removed regardless of the state of this property. This behavior should not be relied upon, so application code should either call fileName() or leave the auto removal functionality enabled.

See also

autoRemove(), remove()

Definition at line 755 of file qtemporaryfile.cpp.

References d.

Referenced by createTemporaryItemCopy().

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setFileTemplate()

void QTemporaryFile::setFileTemplate

(

const QString &

name

)

Sets the static portion of the file name to name.

If the file template contains XXXXXX that will automatically be replaced with the unique part of the filename, otherwise a filename will be determined automatically based on the static portion specified.

If name contains a relative file path, the path will be relative to the current working directory. You can use QDir::tempPath() to construct name if you want use the system's temporary directory. It is important to specify the correct directory if the rename() function will be called, as QTemporaryFile can only rename files within the same volume / filesystem as the temporary file itself was created on.

See also

fileTemplate()

Definition at line 809 of file qtemporaryfile.cpp.

References d.

Friends And Related Symbol Documentation

QFile

friend class QFile

friend

Definition at line 59 of file qtemporaryfile.h.

QLockFilePrivate

friend class QLockFilePrivate

friend

Definition at line 60 of file qtemporaryfile.h.

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The documentation for this class was generated from the following files:

• qtbase/src/corelib/io/qtemporaryfile.h
• qtbase/src/corelib/io/qtemporaryfile.cpp