#[repr(C)]pub struct QSaveFile { /* private fields */ }
Expand description
The QSaveFile class provides an interface for safely writing to files.
C++ class: QSaveFile
.
The QSaveFile class provides an interface for safely writing to files.
QSaveFile is an I/O device for writing text and binary files, without losing existing data if the writing operation fails.
While writing, the contents will be written to a temporary file, and if no error happened, commit() will move it to the final file. This ensures that no data at the final file is lost in case an error happens while writing, and no partially-written file is ever present at the final location. Always use QSaveFile when saving entire documents to disk.
QSaveFile automatically detects errors while writing, such as the full partition situation, where write() cannot write all the bytes. It will remember that an error happened, and will discard the temporary file in commit().
Much like with QFile, the file is opened with open(). Data is usually read and written using QDataStream or QTextStream, but you can also call the QIODevice-inherited functions read(), readLine(), readAll(), write().
Unlike QFile, calling close() is not allowed. commit() replaces it. If commit() was not called and the QSaveFile instance is destroyed, the temporary file is discarded.
To abort saving due to an application error, call cancelWriting(), so that even a call to commit() later on will not save.
Implementations§
source§impl QSaveFile
impl QSaveFile
sourcepub unsafe fn cancel_writing(&self)
pub unsafe fn cancel_writing(&self)
Cancels writing the new file.
Calls C++ function: void QSaveFile::cancelWriting()
.
Cancels writing the new file.
If the application changes its mind while saving, it can call cancelWriting(), which sets an error code so that commit() will discard the temporary file.
Alternatively, it can simply make sure not to call commit().
Further write operations are possible after calling this method, but none of it will have any effect, the written file will be discarded.
This method has no effect when direct write fallback is used. This is the case when saving over an existing file in a readonly directory: no temporary file can be created, so the existing file is overwritten no matter what, and cancelWriting() cannot do anything about that, the contents of the existing file will be lost.
See also commit().
sourcepub unsafe fn commit(&self) -> bool
pub unsafe fn commit(&self) -> bool
Commits the changes to disk, if all previous writes were successful.
Calls C++ function: bool QSaveFile::commit()
.
Commits the changes to disk, if all previous writes were successful.
It is mandatory to call this at the end of the saving operation, otherwise the file will be discarded.
If an error happened during writing, deletes the temporary file and returns false
. Otherwise, renames it to the final fileName and returns true
on success. Finally, closes the device.
See also cancelWriting().
sourcepub unsafe fn direct_write_fallback(&self) -> bool
pub unsafe fn direct_write_fallback(&self) -> bool
Returns true
if the fallback solution for saving files in read-only directories is enabled.
Calls C++ function: bool QSaveFile::directWriteFallback() const
.
Returns true
if the fallback solution for saving files in read-only directories is enabled.
See also setDirectWriteFallback().
sourcepub unsafe fn file_name(&self) -> CppBox<QString>
pub unsafe fn file_name(&self) -> CppBox<QString>
Reimplemented from QFileDevice::fileName().
Calls C++ function: virtual QString QSaveFile::fileName() const
.
Reimplemented from QFileDevice::fileName().
Returns the name set by setFileName() or to the QSaveFile constructor.
See also setFileName().
sourcepub unsafe fn meta_object(&self) -> Ptr<QMetaObject>
pub unsafe fn meta_object(&self) -> Ptr<QMetaObject>
Calls C++ function: virtual const QMetaObject* QSaveFile::metaObject() const
.
sourcepub unsafe fn from_q_string(
name: impl CastInto<Ref<QString>>
) -> QBox<QSaveFile>
pub unsafe fn from_q_string( name: impl CastInto<Ref<QString>> ) -> QBox<QSaveFile>
Constructs a new file object to represent the file with the given name.
Calls C++ function: [constructor] void QSaveFile::QSaveFile(const QString& name)
.
Constructs a new file object to represent the file with the given name.
sourcepub unsafe fn from_q_object(
parent: impl CastInto<Ptr<QObject>>
) -> QBox<QSaveFile>
pub unsafe fn from_q_object( parent: impl CastInto<Ptr<QObject>> ) -> QBox<QSaveFile>
Constructs a new file object with the given parent.
Calls C++ function: [constructor] void QSaveFile::QSaveFile(QObject* parent = …)
.
Constructs a new file object with the given parent.
sourcepub unsafe fn from_q_string_q_object(
name: impl CastInto<Ref<QString>>,
parent: impl CastInto<Ptr<QObject>>
) -> QBox<QSaveFile>
pub unsafe fn from_q_string_q_object( name: impl CastInto<Ref<QString>>, parent: impl CastInto<Ptr<QObject>> ) -> QBox<QSaveFile>
Constructs a new file object with the given parent to represent the file with the specified name.
Calls C++ function: [constructor] void QSaveFile::QSaveFile(const QString& name, QObject* parent)
.
Constructs a new file object with the given parent to represent the file with the specified name.
sourcepub unsafe fn new() -> QBox<QSaveFile>
pub unsafe fn new() -> QBox<QSaveFile>
The QSaveFile class provides an interface for safely writing to files.
Calls C++ function: [constructor] void QSaveFile::QSaveFile()
.
The QSaveFile class provides an interface for safely writing to files.
QSaveFile is an I/O device for writing text and binary files, without losing existing data if the writing operation fails.
While writing, the contents will be written to a temporary file, and if no error happened, commit() will move it to the final file. This ensures that no data at the final file is lost in case an error happens while writing, and no partially-written file is ever present at the final location. Always use QSaveFile when saving entire documents to disk.
QSaveFile automatically detects errors while writing, such as the full partition situation, where write() cannot write all the bytes. It will remember that an error happened, and will discard the temporary file in commit().
Much like with QFile, the file is opened with open(). Data is usually read and written using QDataStream or QTextStream, but you can also call the QIODevice-inherited functions read(), readLine(), readAll(), write().
Unlike QFile, calling close() is not allowed. commit() replaces it. If commit() was not called and the QSaveFile instance is destroyed, the temporary file is discarded.
To abort saving due to an application error, call cancelWriting(), so that even a call to commit() later on will not save.
sourcepub unsafe fn open(&self, flags: QFlags<OpenModeFlag>) -> bool
pub unsafe fn open(&self, flags: QFlags<OpenModeFlag>) -> bool
Reimplemented from QIODevice::open().
Calls C++ function: virtual bool QSaveFile::open(QFlags<QIODevice::OpenModeFlag> flags)
.
Reimplemented from QIODevice::open().
Opens the file using OpenMode mode, returning true if successful; otherwise false.
Important: the mode must include QIODevice::WriteOnly. It may also have additional flags, such as QIODevice::Text and QIODevice::Unbuffered.
QIODevice::ReadWrite and QIODevice::Append are not supported at the moment.
See also QIODevice::OpenMode and setFileName().
sourcepub unsafe fn qt_metacall(
&self,
arg1: Call,
arg2: c_int,
arg3: *mut *mut c_void
) -> c_int
pub unsafe fn qt_metacall( &self, arg1: Call, arg2: c_int, arg3: *mut *mut c_void ) -> c_int
Calls C++ function: virtual int QSaveFile::qt_metacall(QMetaObject::Call arg1, int arg2, void** arg3)
.
sourcepub unsafe fn qt_metacast(&self, arg1: *const c_char) -> *mut c_void
pub unsafe fn qt_metacast(&self, arg1: *const c_char) -> *mut c_void
Calls C++ function: virtual void* QSaveFile::qt_metacast(const char* arg1)
.
sourcepub unsafe fn set_direct_write_fallback(&self, enabled: bool)
pub unsafe fn set_direct_write_fallback(&self, enabled: bool)
Allows writing over the existing file if necessary.
Calls C++ function: void QSaveFile::setDirectWriteFallback(bool enabled)
.
Allows writing over the existing file if necessary.
QSaveFile creates a temporary file in the same directory as the final file and atomically renames it. However this is not possible if the directory permissions do not allow creating new files. In order to preserve atomicity guarantees, open() fails when it cannot create the temporary file.
In order to allow users to edit files with write permissions in a directory with restricted permissions, call setDirectWriteFallback() with enabled set to true, and the following calls to open() will fallback to opening the existing file directly and writing into it, without the use of a temporary file. This does not have atomicity guarantees, i.e. an application crash or for instance a power failure could lead to a partially-written file on disk. It also means cancelWriting() has no effect, in such a case.
Typically, to save documents edited by the user, call setDirectWriteFallback(true), and to save application internal files (configuration files, data files, ...), keep the default setting which ensures atomicity.
See also directWriteFallback().
sourcepub unsafe fn set_file_name(&self, name: impl CastInto<Ref<QString>>)
pub unsafe fn set_file_name(&self, name: impl CastInto<Ref<QString>>)
Sets the name of the file. The name can have no path, a relative path, or an absolute path.
Calls C++ function: void QSaveFile::setFileName(const QString& name)
.
Sets the name of the file. The name can have no path, a relative path, or an absolute path.
See also QFile::setFileName() and fileName().
sourcepub unsafe fn static_meta_object() -> Ref<QMetaObject>
pub unsafe fn static_meta_object() -> Ref<QMetaObject>
Returns a reference to the staticMetaObject
field.
Methods from Deref<Target = QFileDevice>§
sourcepub unsafe fn at_end(&self) -> bool
pub unsafe fn at_end(&self) -> bool
Reimplemented from QIODevice::atEnd().
Calls C++ function: virtual bool QFileDevice::atEnd() const
.
Reimplemented from QIODevice::atEnd().
Returns true
if the end of the file has been reached; otherwise returns false.
For regular empty files on Unix (e.g. those in /proc
), this function returns true
, since the file system reports that the size of such a file is 0. Therefore, you should not depend on atEnd() when reading data from such a file, but rather call read() until no more data can be read.
sourcepub unsafe fn close(&self)
pub unsafe fn close(&self)
Reimplemented from QIODevice::close().
Calls C++ function: virtual void QFileDevice::close()
.
Reimplemented from QIODevice::close().
Calls QFileDevice::flush() and closes the file. Errors from flush are ignored.
See also QIODevice::close().
sourcepub unsafe fn error(&self) -> FileError
pub unsafe fn error(&self) -> FileError
Returns the file error status.
Calls C++ function: QFileDevice::FileError QFileDevice::error() const
.
Returns the file error status.
The I/O device status returns an error code. For example, if open() returns false
, or a read/write operation returns -1, this function can be called to find out the reason why the operation failed.
See also unsetError().
sourcepub unsafe fn file_name(&self) -> CppBox<QString>
pub unsafe fn file_name(&self) -> CppBox<QString>
Returns the name of the file. The default implementation in QFileDevice returns a null string.
Calls C++ function: virtual QString QFileDevice::fileName() const
.
Returns the name of the file. The default implementation in QFileDevice returns a null string.
sourcepub unsafe fn file_time(&self, time: FileTime) -> CppBox<QDateTime>
Available on cpp_lib_version="5.11.3"
or cpp_lib_version="5.12.2"
or cpp_lib_version="5.13.0"
or cpp_lib_version="5.14.0"
only.
pub unsafe fn file_time(&self, time: FileTime) -> CppBox<QDateTime>
cpp_lib_version="5.11.3"
or cpp_lib_version="5.12.2"
or cpp_lib_version="5.13.0"
or cpp_lib_version="5.14.0"
only.Returns the file time specified by time. If the time cannot be determined return QDateTime() (an invalid date time).
Calls C++ function: QDateTime QFileDevice::fileTime(QFileDevice::FileTime time) const
.
Returns the file time specified by time. If the time cannot be determined return QDateTime() (an invalid date time).
This function was introduced in Qt 5.10.
See also setFileTime(), FileTime, and QDateTime::isValid().
sourcepub unsafe fn flush(&self) -> bool
pub unsafe fn flush(&self) -> bool
Flushes any buffered data to the file. Returns true
if successful; otherwise returns false
.
Calls C++ function: bool QFileDevice::flush()
.
Flushes any buffered data to the file. Returns true
if successful; otherwise returns false
.
sourcepub unsafe fn handle(&self) -> c_int
pub unsafe fn handle(&self) -> c_int
Returns the file handle of the file.
Calls C++ function: int QFileDevice::handle() const
.
Returns the file handle of the file.
This is a small positive integer, suitable for use with C library functions such as fdopen()
and fcntl()
. On systems that use file descriptors for sockets (i.e. Unix systems, but not Windows) the handle can be used with QSocketNotifier as well.
If the file is not open, or there is an error, handle() returns -1.
See also QSocketNotifier.
sourcepub unsafe fn is_sequential(&self) -> bool
pub unsafe fn is_sequential(&self) -> bool
Reimplemented from QIODevice::isSequential().
Calls C++ function: virtual bool QFileDevice::isSequential() const
.
Reimplemented from QIODevice::isSequential().
Returns true
if the file can only be manipulated sequentially; otherwise returns false
.
Most files support random-access, but some special files may not.
See also QIODevice::isSequential().
sourcepub unsafe fn map_3a(
&self,
offset: i64,
size: i64,
flags: MemoryMapFlags
) -> *mut c_uchar
pub unsafe fn map_3a( &self, offset: i64, size: i64, flags: MemoryMapFlags ) -> *mut c_uchar
Maps size bytes of the file into memory starting at offset. A file should be open for a map to succeed but the file does not need to stay open after the memory has been mapped. When the QFile is destroyed or a new file is opened with this object, any maps that have not been unmapped will automatically be unmapped.
Calls C++ function: unsigned char* QFileDevice::map(qint64 offset, qint64 size, QFileDevice::MemoryMapFlags flags = …)
.
Maps size bytes of the file into memory starting at offset. A file should be open for a map to succeed but the file does not need to stay open after the memory has been mapped. When the QFile is destroyed or a new file is opened with this object, any maps that have not been unmapped will automatically be unmapped.
The mapping will have the same open mode as the file (read and/or write), except when using MapPrivateOption, in which case it is always possible to write to the mapped memory.
Any mapping options can be passed through flags.
Returns a pointer to the memory or 0 if there is an error.
See also unmap().
sourcepub unsafe fn map_2a(&self, offset: i64, size: i64) -> *mut c_uchar
pub unsafe fn map_2a(&self, offset: i64, size: i64) -> *mut c_uchar
Maps size bytes of the file into memory starting at offset. A file should be open for a map to succeed but the file does not need to stay open after the memory has been mapped. When the QFile is destroyed or a new file is opened with this object, any maps that have not been unmapped will automatically be unmapped.
Calls C++ function: unsigned char* QFileDevice::map(qint64 offset, qint64 size)
.
Maps size bytes of the file into memory starting at offset. A file should be open for a map to succeed but the file does not need to stay open after the memory has been mapped. When the QFile is destroyed or a new file is opened with this object, any maps that have not been unmapped will automatically be unmapped.
The mapping will have the same open mode as the file (read and/or write), except when using MapPrivateOption, in which case it is always possible to write to the mapped memory.
Any mapping options can be passed through flags.
Returns a pointer to the memory or 0 if there is an error.
See also unmap().
sourcepub unsafe fn meta_object(&self) -> Ptr<QMetaObject>
pub unsafe fn meta_object(&self) -> Ptr<QMetaObject>
Calls C++ function: virtual const QMetaObject* QFileDevice::metaObject() const
.
sourcepub unsafe fn permissions(&self) -> QFlags<Permission>
pub unsafe fn permissions(&self) -> QFlags<Permission>
Returns the complete OR-ed together combination of QFile::Permission for the file.
Calls C++ function: virtual QFlags<QFileDevice::Permission> QFileDevice::permissions() const
.
Returns the complete OR-ed together combination of QFile::Permission for the file.
See also setPermissions().
sourcepub unsafe fn pos(&self) -> i64
pub unsafe fn pos(&self) -> i64
Reimplemented from QIODevice::pos().
Calls C++ function: virtual qint64 QFileDevice::pos() const
.
Reimplemented from QIODevice::pos().
sourcepub unsafe fn qt_metacall(
&self,
arg1: Call,
arg2: c_int,
arg3: *mut *mut c_void
) -> c_int
pub unsafe fn qt_metacall( &self, arg1: Call, arg2: c_int, arg3: *mut *mut c_void ) -> c_int
Calls C++ function: virtual int QFileDevice::qt_metacall(QMetaObject::Call arg1, int arg2, void** arg3)
.
sourcepub unsafe fn qt_metacast(&self, arg1: *const c_char) -> *mut c_void
pub unsafe fn qt_metacast(&self, arg1: *const c_char) -> *mut c_void
Calls C++ function: virtual void* QFileDevice::qt_metacast(const char* arg1)
.
sourcepub unsafe fn resize(&self, sz: i64) -> bool
pub unsafe fn resize(&self, sz: i64) -> bool
Sets the file size (in bytes) sz. Returns true
if the resize succeeds; false otherwise. If sz is larger than the file currently is, the new bytes will be set to 0; if sz is smaller, the file is simply truncated.
Calls C++ function: virtual bool QFileDevice::resize(qint64 sz)
.
Sets the file size (in bytes) sz. Returns true
if the resize succeeds; false otherwise. If sz is larger than the file currently is, the new bytes will be set to 0; if sz is smaller, the file is simply truncated.
Warning: This function can fail if the file doesn't exist.
See also size().
sourcepub unsafe fn seek(&self, offset: i64) -> bool
pub unsafe fn seek(&self, offset: i64) -> bool
Reimplemented from QIODevice::seek().
Calls C++ function: virtual bool QFileDevice::seek(qint64 offset)
.
Reimplemented from QIODevice::seek().
For random-access devices, this function sets the current position to pos, returning true on success, or false if an error occurred. For sequential devices, the default behavior is to do nothing and return false.
Seeking beyond the end of a file: If the position is beyond the end of a file, then seek() will not immediately extend the file. If a write is performed at this position, then the file will be extended. The content of the file between the previous end of file and the newly written data is UNDEFINED and varies between platforms and file systems.
sourcepub unsafe fn set_file_time(
&self,
new_date: impl CastInto<Ref<QDateTime>>,
file_time: FileTime
) -> bool
Available on cpp_lib_version="5.11.3"
or cpp_lib_version="5.12.2"
or cpp_lib_version="5.13.0"
or cpp_lib_version="5.14.0"
only.
pub unsafe fn set_file_time( &self, new_date: impl CastInto<Ref<QDateTime>>, file_time: FileTime ) -> bool
cpp_lib_version="5.11.3"
or cpp_lib_version="5.12.2"
or cpp_lib_version="5.13.0"
or cpp_lib_version="5.14.0"
only.Sets the file time specified by fileTime to newDate, returning true if successful; otherwise returns false.
Calls C++ function: bool QFileDevice::setFileTime(const QDateTime& newDate, QFileDevice::FileTime fileTime)
.
sourcepub unsafe fn set_permissions(
&self,
permission_spec: QFlags<Permission>
) -> bool
pub unsafe fn set_permissions( &self, permission_spec: QFlags<Permission> ) -> bool
Sets the permissions for the file to the permissions specified. Returns true
if successful, or false
if the permissions cannot be modified.
Calls C++ function: virtual bool QFileDevice::setPermissions(QFlags<QFileDevice::Permission> permissionSpec)
.
Sets the permissions for the file to the permissions specified. Returns true
if successful, or false
if the permissions cannot be modified.
Warning: This function does not manipulate ACLs, which may limit its effectiveness.
See also permissions().
sourcepub unsafe fn size(&self) -> i64
pub unsafe fn size(&self) -> i64
Reimplemented from QIODevice::size().
Calls C++ function: virtual qint64 QFileDevice::size() const
.
Reimplemented from QIODevice::size().
Returns the size of the file.
For regular empty files on Unix (e.g. those in /proc
), this function returns 0; the contents of such a file are generated on demand in response to you calling read().
sourcepub unsafe fn unmap(&self, address: *mut c_uchar) -> bool
pub unsafe fn unmap(&self, address: *mut c_uchar) -> bool
Unmaps the memory address.
Calls C++ function: bool QFileDevice::unmap(unsigned char* address)
.
sourcepub unsafe fn unset_error(&self)
pub unsafe fn unset_error(&self)
Sets the file's error to QFileDevice::NoError.
Calls C++ function: void QFileDevice::unsetError()
.
Sets the file’s error to QFileDevice::NoError.
See also error().
Methods from Deref<Target = QIODevice>§
sourcepub fn ready_read(&self) -> Signal<()>
pub fn ready_read(&self) -> Signal<()>
This signal is emitted once every time new data is available for reading from the device's current read channel. It will only be emitted again once new data is available, such as when a new payload of network data has arrived on your network socket, or when a new block of data has been appended to your device.
Returns a built-in Qt signal QIODevice::readyRead
that can be passed to qt_core::Signal::connect
.
This signal is emitted once every time new data is available for reading from the device’s current read channel. It will only be emitted again once new data is available, such as when a new payload of network data has arrived on your network socket, or when a new block of data has been appended to your device.
readyRead() is not emitted recursively; if you reenter the event loop or call waitForReadyRead() inside a slot connected to the readyRead() signal, the signal will not be reemitted (although waitForReadyRead() may still return true).
Note for developers implementing classes derived from QIODevice: you should always emit readyRead() when new data has arrived (do not emit it only because there's data still to be read in your buffers). Do not emit readyRead() in other conditions.
See also bytesWritten().
sourcepub fn channel_ready_read(&self) -> Signal<(c_int,)>
pub fn channel_ready_read(&self) -> Signal<(c_int,)>
This signal is emitted when new data is available for reading from the device. The channel argument is set to the index of the read channel on which the data has arrived. Unlike readyRead(), it is emitted regardless of the current read channel.
Returns a built-in Qt signal QIODevice::channelReadyRead
that can be passed to qt_core::Signal::connect
.
This signal is emitted when new data is available for reading from the device. The channel argument is set to the index of the read channel on which the data has arrived. Unlike readyRead(), it is emitted regardless of the current read channel.
channelReadyRead() can be emitted recursively - even for the same channel.
This function was introduced in Qt 5.7.
See also readyRead() and channelBytesWritten().
sourcepub fn bytes_written(&self) -> Signal<(i64,)>
pub fn bytes_written(&self) -> Signal<(i64,)>
This signal is emitted every time a payload of data has been written to the device's current write channel. The bytes argument is set to the number of bytes that were written in this payload.
Returns a built-in Qt signal QIODevice::bytesWritten
that can be passed to qt_core::Signal::connect
.
This signal is emitted every time a payload of data has been written to the device’s current write channel. 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 readyRead().
sourcepub fn channel_bytes_written(&self) -> Signal<(c_int, i64)>
pub fn channel_bytes_written(&self) -> Signal<(c_int, i64)>
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, while channel is the channel they were written to. Unlike bytesWritten(), it is emitted regardless of the current write channel.
Returns a built-in Qt signal QIODevice::channelBytesWritten
that can be passed to qt_core::Signal::connect
.
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, while channel is the channel they were written to. Unlike bytesWritten(), it is emitted regardless of the current write channel.
channelBytesWritten() can be emitted recursively - even for the same channel.
This function was introduced in Qt 5.7.
See also bytesWritten() and channelReadyRead().
sourcepub fn about_to_close(&self) -> Signal<()>
pub fn about_to_close(&self) -> Signal<()>
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).
Returns a built-in Qt signal QIODevice::aboutToClose
that can be passed to qt_core::Signal::connect
.
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).
sourcepub fn read_channel_finished(&self) -> Signal<()>
pub fn read_channel_finished(&self) -> Signal<()>
This signal is emitted when the input (reading) stream is closed in this device. It is emitted as soon as the closing is detected, which means that there might still be data available for reading with read().
Returns a built-in Qt signal QIODevice::readChannelFinished
that can be passed to qt_core::Signal::connect
.
sourcepub unsafe fn at_end(&self) -> bool
pub unsafe fn at_end(&self) -> bool
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
.
Calls C++ function: virtual bool QIODevice::atEnd() const
.
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 macOS, or console input / stdin
on all platforms).
See also bytesAvailable(), read(), and isSequential().
sourcepub unsafe fn bytes_available(&self) -> i64
pub unsafe fn bytes_available(&self) -> i64
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.
Calls C++ function: virtual qint64 QIODevice::bytesAvailable() const
.
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 the buffer of QIODevice. Example:
qint64 CustomDevice::bytesAvailable() const { return buffer.size() + QIODevice::bytesAvailable(); }
See also bytesToWrite(), readyRead(), and isSequential().
sourcepub unsafe fn bytes_to_write(&self) -> i64
pub unsafe fn bytes_to_write(&self) -> i64
For buffered devices, this function returns the number of bytes waiting to be written. For devices with no buffer, this function returns 0.
Calls C++ function: virtual qint64 QIODevice::bytesToWrite() const
.
For buffered devices, this function returns the number of bytes waiting to be written. For devices with no buffer, this function returns 0.
Subclasses that reimplement this function must call the base implementation in order to include the size of the buffer of QIODevice.
See also bytesAvailable(), bytesWritten(), and isSequential().
sourcepub unsafe fn can_read_line(&self) -> bool
pub unsafe fn can_read_line(&self) -> bool
Returns true
if a complete line of data can be read from the device; otherwise returns false
.
Calls C++ function: virtual bool QIODevice::canReadLine() const
.
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(); }
sourcepub unsafe fn close(&self)
pub unsafe fn close(&self)
First emits aboutToClose(), then closes the device and sets its OpenMode to NotOpen. The error string is also reset.
Calls C++ function: virtual void QIODevice::close()
.
First emits aboutToClose(), then closes the device and sets its OpenMode to NotOpen. The error string is also reset.
See also setOpenMode() and OpenMode.
sourcepub unsafe fn commit_transaction(&self)
pub unsafe fn commit_transaction(&self)
Completes a read transaction.
Calls C++ function: void QIODevice::commitTransaction()
.
Completes a read transaction.
For sequential devices, all data recorded in the internal buffer during the transaction will be discarded.
This function was introduced in Qt 5.7.
See also startTransaction() and rollbackTransaction().
sourcepub unsafe fn current_read_channel(&self) -> c_int
pub unsafe fn current_read_channel(&self) -> c_int
Returns the index of the current read channel.
Calls C++ function: int QIODevice::currentReadChannel() const
.
Returns the index of the current read channel.
This function was introduced in Qt 5.7.
See also setCurrentReadChannel(), readChannelCount(), and QProcess.
sourcepub unsafe fn current_write_channel(&self) -> c_int
pub unsafe fn current_write_channel(&self) -> c_int
Returns the the index of the current write channel.
Calls C++ function: int QIODevice::currentWriteChannel() const
.
Returns the the index of the current write channel.
This function was introduced in Qt 5.7.
See also setCurrentWriteChannel() and writeChannelCount().
sourcepub unsafe fn error_string(&self) -> CppBox<QString>
pub unsafe fn error_string(&self) -> CppBox<QString>
Returns a human-readable description of the last device error that occurred.
Calls C++ function: QString QIODevice::errorString() const
.
Returns a human-readable description of the last device error that occurred.
See also setErrorString().
sourcepub unsafe fn get_char(&self, c: *mut c_char) -> bool
pub unsafe fn get_char(&self, c: *mut c_char) -> bool
Reads one character from the device and stores it in c. If c is 0, the character is discarded. Returns true
on success; otherwise returns false
.
Calls C++ function: bool QIODevice::getChar(char* c)
.
sourcepub unsafe fn is_open(&self) -> bool
pub unsafe fn is_open(&self) -> bool
Returns true
if the device is open; otherwise returns false
. A device is open if it can be read from and/or written to. By default, this function returns false
if openMode() returns NotOpen
.
Calls C++ function: bool QIODevice::isOpen() const
.
sourcepub unsafe fn is_readable(&self) -> bool
pub unsafe fn is_readable(&self) -> bool
Returns true
if data can be read from the device; otherwise returns false. Use bytesAvailable() to determine how many bytes can be read.
Calls C++ function: bool QIODevice::isReadable() const
.
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.
sourcepub unsafe fn is_sequential(&self) -> bool
pub unsafe fn is_sequential(&self) -> bool
Returns true
if this device is sequential; otherwise returns false.
Calls C++ function: virtual bool QIODevice::isSequential() const
.
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.
See also bytesAvailable().
sourcepub unsafe fn is_text_mode_enabled(&self) -> bool
pub unsafe fn is_text_mode_enabled(&self) -> bool
Returns true
if the Text flag is enabled; otherwise returns false
.
Calls C++ function: bool QIODevice::isTextModeEnabled() const
.
Returns true
if the Text flag is enabled; otherwise returns false
.
See also setTextModeEnabled().
sourcepub unsafe fn is_transaction_started(&self) -> bool
pub unsafe fn is_transaction_started(&self) -> bool
Returns true
if a transaction is in progress on the device, otherwise false
.
Calls C++ function: bool QIODevice::isTransactionStarted() const
.
Returns true
if a transaction is in progress on the device, otherwise false
.
This function was introduced in Qt 5.7.
See also startTransaction().
sourcepub unsafe fn is_writable(&self) -> bool
pub unsafe fn is_writable(&self) -> bool
Returns true
if data can be written to the device; otherwise returns false.
Calls C++ function: bool QIODevice::isWritable() const
.
sourcepub unsafe fn meta_object(&self) -> Ptr<QMetaObject>
pub unsafe fn meta_object(&self) -> Ptr<QMetaObject>
Calls C++ function: virtual const QMetaObject* QIODevice::metaObject() const
.
sourcepub unsafe fn open(&self, mode: QFlags<OpenModeFlag>) -> bool
pub unsafe fn open(&self, mode: QFlags<OpenModeFlag>) -> bool
Opens the device and sets its OpenMode to mode. Returns true
if successful; otherwise returns false
. This function should be called from any reimplementations of open() or other functions that open the device.
Calls C++ function: virtual bool QIODevice::open(QFlags<QIODevice::OpenModeFlag> mode)
.
sourcepub unsafe fn open_mode(&self) -> QFlags<OpenModeFlag>
pub unsafe fn open_mode(&self) -> QFlags<OpenModeFlag>
sourcepub unsafe fn peek_2a(&self, data: *mut c_char, maxlen: i64) -> i64
pub unsafe fn peek_2a(&self, data: *mut c_char, maxlen: i64) -> i64
Reads at most maxSize bytes from the device into data, without side effects (i.e., if you call read() after peek(), you will get the same data). Returns the number of bytes read. If an error occurs, such as when attempting to peek a device opened in WriteOnly mode, this function returns -1.
Calls C++ function: qint64 QIODevice::peek(char* data, qint64 maxlen)
.
Reads at most maxSize bytes from the device into data, without side effects (i.e., if you call read() after peek(), you will get the same data). Returns the number of bytes read. If an error occurs, such as when attempting to peek a device opened in WriteOnly mode, this function returns -1.
0 is returned when no more data is available for reading.
Example:
bool isExeFile(QFile *file) { char buf[2]; if (file->peek(buf, sizeof(buf)) == sizeof(buf)) return (buf[0] == ‘M’ && buf[1] == ‘Z’); return false; }
This function was introduced in Qt 4.1.
See also read().
sourcepub unsafe fn peek_1a(&self, maxlen: i64) -> CppBox<QByteArray>
pub unsafe fn peek_1a(&self, maxlen: i64) -> CppBox<QByteArray>
This is an overloaded function.
Calls C++ function: QByteArray QIODevice::peek(qint64 maxlen)
.
This is an overloaded function.
Peeks at most maxSize bytes from the device, returning the data peeked as a QByteArray.
Example:
bool isExeFile(QFile *file) { return file->peek(2) == “MZ”; }
This function has no way of reporting errors; returning an empty QByteArray can mean either that no data was currently available for peeking, or that an error occurred.
This function was introduced in Qt 4.1.
See also read().
sourcepub unsafe fn pos(&self) -> i64
pub unsafe fn pos(&self) -> i64
For random-access devices, this function returns the position that data is written to or read from. For sequential devices or closed devices, where there is no concept of a "current position", 0 is returned.
Calls C++ function: virtual qint64 QIODevice::pos() const
.
For random-access devices, this function returns the position that data is written to or read from. For sequential devices or closed devices, where there is no concept of a “current position”, 0 is returned.
The current read/write position of the device is maintained internally by QIODevice, so reimplementing this function is not necessary. When subclassing QIODevice, use QIODevice::seek() to notify QIODevice about changes in the device position.
See also isSequential() and seek().
sourcepub unsafe fn put_char(&self, c: c_char) -> bool
pub unsafe fn put_char(&self, c: c_char) -> bool
Writes the character c to the device. Returns true
on success; otherwise returns false
.
Calls C++ function: bool QIODevice::putChar(char c)
.
sourcepub unsafe fn qt_metacall(
&self,
arg1: Call,
arg2: c_int,
arg3: *mut *mut c_void
) -> c_int
pub unsafe fn qt_metacall( &self, arg1: Call, arg2: c_int, arg3: *mut *mut c_void ) -> c_int
Calls C++ function: virtual int QIODevice::qt_metacall(QMetaObject::Call arg1, int arg2, void** arg3)
.
sourcepub unsafe fn qt_metacast(&self, arg1: *const c_char) -> *mut c_void
pub unsafe fn qt_metacast(&self, arg1: *const c_char) -> *mut c_void
Calls C++ function: virtual void* QIODevice::qt_metacast(const char* arg1)
.
sourcepub unsafe fn read_2a(&self, data: *mut c_char, maxlen: i64) -> i64
pub unsafe fn read_2a(&self, data: *mut c_char, maxlen: i64) -> i64
Reads at most maxSize bytes from the device into data, and returns the number of bytes read. If an error occurs, such as when attempting to read from a device opened in WriteOnly mode, this function returns -1.
Calls C++ function: qint64 QIODevice::read(char* data, qint64 maxlen)
.
Reads at most maxSize bytes from the device into data, and returns the number of bytes read. If an error occurs, such as when attempting to read from a device opened in WriteOnly mode, this function returns -1.
0 is returned when no more data is available for reading. However, reading past the end of the stream is considered an error, so this function returns -1 in those cases (that is, reading on a closed socket or after a process has died).
sourcepub unsafe fn read_1a(&self, maxlen: i64) -> CppBox<QByteArray>
pub unsafe fn read_1a(&self, maxlen: i64) -> CppBox<QByteArray>
This is an overloaded function.
Calls C++ function: QByteArray QIODevice::read(qint64 maxlen)
.
This is an overloaded function.
Reads at most maxSize bytes from the device, and returns the data read as a QByteArray.
This function has no way of reporting errors; returning an empty QByteArray can mean either that no data was currently available for reading, or that an error occurred.
sourcepub unsafe fn read_all(&self) -> CppBox<QByteArray>
pub unsafe fn read_all(&self) -> CppBox<QByteArray>
Reads all remaining data from the device, and returns it as a byte array.
Calls C++ function: QByteArray QIODevice::readAll()
.
Reads all remaining data from the device, and returns it as a byte array.
This function has no way of reporting errors; returning an empty QByteArray can mean either that no data was currently available for reading, or that an error occurred.
sourcepub unsafe fn read_channel_count(&self) -> c_int
pub unsafe fn read_channel_count(&self) -> c_int
Returns the number of available read channels if the device is open; otherwise returns 0.
Calls C++ function: int QIODevice::readChannelCount() const
.
Returns the number of available read channels if the device is open; otherwise returns 0.
This function was introduced in Qt 5.7.
See also writeChannelCount() and QProcess.
sourcepub unsafe fn read_line_2a(&self, data: *mut c_char, maxlen: i64) -> i64
pub unsafe fn read_line_2a(&self, data: *mut c_char, maxlen: i64) -> i64
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. If a line could not be read but no error ocurred, this function returns 0. If an error occurs, this function returns the length of what could be read, or -1 if nothing was read.
Calls C++ function: qint64 QIODevice::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. If a line could not be read but no error ocurred, this function returns 0. If an error occurs, this function returns the length of what could be read, or -1 if nothing was read.
A terminating '\0' byte is always appended to data, so maxSize must be larger than 1.
Data is read until either of the following conditions are met:
- The first '\n' character is read.
- maxSize - 1 bytes are read.
- The end of the device data is detected.
For example, the following code reads a line of characters from a file:
QFile file(“box.txt”); if (file.open(QFile::ReadOnly)) { char buf[1024]; qint64 lineLength = file.readLine(buf, sizeof(buf)); if (lineLength != -1) { // the line is available in buf } }
The newline character ('\n') is included in the buffer. If a newline is not encountered before maxSize - 1 bytes are read, a newline will not be inserted into the buffer. On windows newline characters are replaced with '\n'.
This function calls readLineData(), which is implemented using repeated calls to getChar(). You can provide a more efficient implementation by reimplementing readLineData() in your own subclass.
sourcepub unsafe fn read_line_1a(&self, maxlen: i64) -> CppBox<QByteArray>
pub unsafe fn read_line_1a(&self, maxlen: i64) -> CppBox<QByteArray>
This is an overloaded function.
Calls C++ function: QByteArray QIODevice::readLine(qint64 maxlen = …)
.
This is an overloaded function.
Reads a line from the device, but no more than maxSize characters, and returns the result as a byte array.
This function has no way of reporting errors; returning an empty QByteArray can mean either that no data was currently available for reading, or that an error occurred.
sourcepub unsafe fn read_line_0a(&self) -> CppBox<QByteArray>
pub unsafe fn read_line_0a(&self) -> CppBox<QByteArray>
This is an overloaded function.
Calls C++ function: QByteArray QIODevice::readLine()
.
This is an overloaded function.
Reads a line from the device, but no more than maxSize characters, and returns the result as a byte array.
This function has no way of reporting errors; returning an empty QByteArray can mean either that no data was currently available for reading, or that an error occurred.
sourcepub unsafe fn reset(&self) -> bool
pub unsafe fn reset(&self) -> bool
Seeks to the start of input for random-access devices. Returns true on success; otherwise returns false
(for example, if the device is not open).
Calls C++ function: virtual bool QIODevice::reset()
.
Seeks to the start of input for random-access devices. Returns true on success; otherwise returns false
(for example, if the device is not open).
Note that when using a QTextStream on a QFile, calling reset() on the QFile will not have the expected result because QTextStream buffers the file. Use the QTextStream::seek() function instead.
See also seek().
sourcepub unsafe fn rollback_transaction(&self)
pub unsafe fn rollback_transaction(&self)
Rolls back a read transaction.
Calls C++ function: void QIODevice::rollbackTransaction()
.
Rolls back a read transaction.
Restores the input stream to the point of the startTransaction() call. This function is commonly used to rollback the transaction when an incomplete read was detected prior to committing the transaction.
This function was introduced in Qt 5.7.
See also startTransaction() and commitTransaction().
sourcepub unsafe fn seek(&self, pos: i64) -> bool
pub unsafe fn seek(&self, pos: i64) -> bool
For random-access devices, this function sets the current position to pos, returning true on success, or false if an error occurred. For sequential devices, the default behavior is to produce a warning and return false.
Calls C++ function: virtual bool QIODevice::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. For sequential devices, the default behavior is to produce a warning and return false.
When subclassing QIODevice, you must call QIODevice::seek() at the start of your function to ensure integrity with QIODevice's built-in buffer.
See also pos() and isSequential().
sourcepub unsafe fn set_current_read_channel(&self, channel: c_int)
pub unsafe fn set_current_read_channel(&self, channel: c_int)
Sets the current read channel of the QIODevice to the given channel. The current input channel is used by the functions read(), readAll(), readLine(), and getChar(). It also determines which channel triggers QIODevice to emit readyRead().
Calls C++ function: void QIODevice::setCurrentReadChannel(int channel)
.
Sets the current read channel of the QIODevice to the given channel. The current input channel is used by the functions read(), readAll(), readLine(), and getChar(). It also determines which channel triggers QIODevice to emit readyRead().
This function was introduced in Qt 5.7.
See also currentReadChannel(), readChannelCount(), and QProcess.
sourcepub unsafe fn set_current_write_channel(&self, channel: c_int)
pub unsafe fn set_current_write_channel(&self, channel: c_int)
Sets the current write channel of the QIODevice to the given channel. The current output channel is used by the functions write(), putChar(). It also determines which channel triggers QIODevice to emit bytesWritten().
Calls C++ function: void QIODevice::setCurrentWriteChannel(int channel)
.
Sets the current write channel of the QIODevice to the given channel. The current output channel is used by the functions write(), putChar(). It also determines which channel triggers QIODevice to emit bytesWritten().
This function was introduced in Qt 5.7.
See also currentWriteChannel() and writeChannelCount().
sourcepub unsafe fn set_text_mode_enabled(&self, enabled: bool)
pub unsafe fn set_text_mode_enabled(&self, enabled: bool)
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.
Calls C++ function: void 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().
sourcepub unsafe fn size(&self) -> i64
pub unsafe fn size(&self) -> i64
For open random-access devices, this function returns the size of the device. For open sequential devices, bytesAvailable() is returned.
Calls C++ function: virtual qint64 QIODevice::size() const
.
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.
See also isSequential() and pos().
sourcepub unsafe fn skip(&self, max_size: i64) -> i64
Available on cpp_lib_version="5.11.3"
or cpp_lib_version="5.12.2"
or cpp_lib_version="5.13.0"
or cpp_lib_version="5.14.0"
only.
pub unsafe fn skip(&self, max_size: i64) -> i64
cpp_lib_version="5.11.3"
or cpp_lib_version="5.12.2"
or cpp_lib_version="5.13.0"
or cpp_lib_version="5.14.0"
only.Skips up to maxSize bytes from the device. Returns the number of bytes actually skipped, or -1 on error.
Calls C++ function: qint64 QIODevice::skip(qint64 maxSize)
.
Skips up to maxSize bytes from the device. Returns the number of bytes actually skipped, or -1 on error.
This function does not wait and only discards the data that is already available for reading.
If the device is opened in text mode, end-of-line terminators are translated to '\n' symbols and count as a single byte identically to the read() and peek() behavior.
This function works for all devices, including sequential ones that cannot seek(). It is optimized to skip unwanted data after a peek() call.
For random-access devices, skip() can be used to seek forward from the current position. Negative maxSize values are not allowed.
This function was introduced in Qt 5.10.
sourcepub unsafe fn start_transaction(&self)
pub unsafe fn start_transaction(&self)
Starts a new read transaction on the device.
Calls C++ function: void QIODevice::startTransaction()
.
Starts a new read transaction on the device.
Defines a restorable point within the sequence of read operations. For sequential devices, read data will be duplicated internally to allow recovery in case of incomplete reads. For random-access devices, this function saves the current position. Call commitTransaction() or rollbackTransaction() to finish the transaction.
Note: Nesting transactions is not supported.
This function was introduced in Qt 5.7.
See also commitTransaction() and rollbackTransaction().
sourcepub unsafe fn unget_char(&self, c: c_char)
pub unsafe fn unget_char(&self, c: c_char)
Puts the character c back into the device, and decrements the current position unless the position is 0. This function is usually called to "undo" a getChar() operation, such as when writing a backtracking parser.
Calls C++ function: void QIODevice::ungetChar(char c)
.
Puts the character c back into the device, and decrements the current position unless the position is 0. This function is usually called to “undo” a getChar() operation, such as when writing a backtracking parser.
If c was not previously read from the device, the behavior is undefined.
Note: This function is not available while a transaction is in progress.
sourcepub unsafe fn wait_for_bytes_written(&self, msecs: c_int) -> bool
pub unsafe fn wait_for_bytes_written(&self, msecs: c_int) -> bool
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. If msecs is -1, this function will not time out. For unbuffered devices, it returns immediately.
Calls C++ function: virtual bool QIODevice::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. If msecs is -1, this function will not time out. For unbuffered devices, it returns immediately.
Returns true
if a payload of data was written to the device; otherwise returns false
(i.e. if the operation timed out, or if an error occurred).
This function can operate without an event loop. It is useful when writing non-GUI applications and when performing I/O operations in a non-GUI thread.
If called from within a slot connected to the bytesWritten() signal, bytesWritten() will not be reemitted.
Reimplement this function to provide a blocking API for a custom device. The default implementation does nothing, and returns false
.
Warning: Calling this function from the main (GUI) thread might cause your user interface to freeze.
See also waitForReadyRead().
sourcepub unsafe fn wait_for_ready_read(&self, msecs: c_int) -> bool
pub unsafe fn wait_for_ready_read(&self, msecs: c_int) -> bool
Blocks until new data is available for reading and the readyRead() signal has been emitted, or until msecs milliseconds have passed. If msecs is -1, this function will not time out.
Calls C++ function: virtual bool QIODevice::waitForReadyRead(int msecs)
.
Blocks until new data is available for reading and the readyRead() signal has been emitted, or until msecs milliseconds have passed. If msecs is -1, this function will not time out.
Returns true
if new data is available for reading; otherwise returns false (if the operation timed out or if an error occurred).
This function can operate without an event loop. It is useful when writing non-GUI applications and when performing I/O operations in a non-GUI thread.
If called from within a slot connected to the readyRead() signal, readyRead() will not be reemitted.
Reimplement this function to provide a blocking API for a custom device. The default implementation does nothing, and returns false
.
Warning: Calling this function from the main (GUI) thread might cause your user interface to freeze.
See also waitForBytesWritten().
sourcepub unsafe fn write_char_i64(&self, data: *const c_char, len: i64) -> i64
pub unsafe fn write_char_i64(&self, data: *const c_char, len: i64) -> i64
Writes at most maxSize bytes of data from data to the device. Returns the number of bytes that were actually written, or -1 if an error occurred.
Calls C++ function: qint64 QIODevice::write(const char* data, qint64 len)
.
sourcepub unsafe fn write_char(&self, data: *const c_char) -> i64
pub unsafe fn write_char(&self, data: *const c_char) -> i64
This is an overloaded function.
Calls C++ function: qint64 QIODevice::write(const char* data)
.
This is an overloaded function.
Writes data from a zero-terminated string of 8-bit characters to the device. Returns the number of bytes that were actually written, or -1 if an error occurred. This is equivalent to
... QIODevice::write(data, qstrlen(data)); ...
This function was introduced in Qt 4.5.
sourcepub unsafe fn write_q_byte_array(
&self,
data: impl CastInto<Ref<QByteArray>>
) -> i64
pub unsafe fn write_q_byte_array( &self, data: impl CastInto<Ref<QByteArray>> ) -> i64
This is an overloaded function.
Calls C++ function: qint64 QIODevice::write(const QByteArray& data)
.
sourcepub unsafe fn write_channel_count(&self) -> c_int
pub unsafe fn write_channel_count(&self) -> c_int
Returns the number of available write channels if the device is open; otherwise returns 0.
Calls C++ function: int QIODevice::writeChannelCount() const
.
Returns the number of available write channels if the device is open; otherwise returns 0.
This function was introduced in Qt 5.7.
See also readChannelCount().
Methods from Deref<Target = QObject>§
sourcepub unsafe fn find_child<T>(
&self,
name: &str
) -> Result<QPtr<T>, FindChildError>
pub unsafe fn find_child<T>( &self, name: &str ) -> Result<QPtr<T>, FindChildError>
Finds a child of self
with the specified object name
and casts it to type T
.
The search is performed recursively. If there is more than one child matching the search, the most direct ancestor is returned. If there are several direct ancestors, it is undefined which one will be returned.
Returns an error if there is no child object with object name name
or
the found object cannot be cast to T
.
sourcepub fn destroyed(&self) -> Signal<(*mut QObject,)>
pub fn destroyed(&self) -> Signal<(*mut QObject,)>
This signal is emitted immediately before the object obj is destroyed, and can not be blocked.
Returns a built-in Qt signal QObject::destroyed
that can be passed to qt_core::Signal::connect
.
This signal is emitted immediately before the object obj is destroyed, and can not be blocked.
All the objects's children are destroyed immediately after this signal is emitted.
See also deleteLater() and QPointer.
sourcepub fn object_name_changed(&self) -> Signal<(*const QString,)>
pub fn object_name_changed(&self) -> Signal<(*const QString,)>
This signal is emitted after the object's name has been changed. The new object name is passed as objectName.
Returns a built-in Qt signal QObject::objectNameChanged
that can be passed to qt_core::Signal::connect
.
This signal is emitted after the object’s name has been changed. The new object name is passed as objectName.
Note: This is a private signal. It can be used in signal connections but cannot be emitted by the user.
Note: Notifier signal for property objectName.
See also QObject::objectName.
sourcepub fn slot_delete_later(&self) -> Receiver<()>
pub fn slot_delete_later(&self) -> Receiver<()>
Schedules this object for deletion.
Returns a built-in Qt slot QObject::deleteLater
that can be passed to qt_core::Signal::connect
.
Schedules this object for deletion.
The object will be deleted when control returns to the event loop. If the event loop is not running when this function is called (e.g. deleteLater() is called on an object before QCoreApplication::exec()), the object will be deleted once the event loop is started. If deleteLater() is called after the main event loop has stopped, the object will not be deleted. Since Qt 4.8, if deleteLater() is called on an object that lives in a thread with no running event loop, the object will be destroyed when the thread finishes.
Note that entering and leaving a new event loop (e.g., by opening a modal dialog) will not perform the deferred deletion; for the object to be deleted, the control must return to the event loop from which deleteLater() was called.
Note: It is safe to call this function more than once; when the first deferred deletion event is delivered, any pending events for the object are removed from the event queue.
sourcepub unsafe fn block_signals(&self, b: bool) -> bool
pub unsafe fn block_signals(&self, b: bool) -> bool
If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it). If block is false, no such blocking will occur.
Calls C++ function: bool QObject::blockSignals(bool b)
.
If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it). If block is false, no such blocking will occur.
The return value is the previous value of signalsBlocked().
Note that the destroyed() signal will be emitted even if the signals for this object have been blocked.
Signals emitted while being blocked are not buffered.
See also signalsBlocked() and QSignalBlocker.
sourcepub unsafe fn children(&self) -> Ref<QListOfQObject>
pub unsafe fn children(&self) -> Ref<QListOfQObject>
Returns a list of child objects. The QObjectList class is defined in the <QObject>
header file as the following:
Calls C++ function: const QList<QObject*>& QObject::children() const
.
Returns a list of child objects. The QObjectList class is defined in the <QObject>
header file as the following:
typedef QList<QObject*> QObjectList;
The first child added is the first object in the list and the last child added is the last object in the list, i.e. new children are appended at the end.
Note that the list order changes when QWidget children are raised or lowered. A widget that is raised becomes the last object in the list, and a widget that is lowered becomes the first object in the list.
See also findChild(), findChildren(), parent(), and setParent().
sourcepub unsafe fn delete_later(&self)
pub unsafe fn delete_later(&self)
Schedules this object for deletion.
Calls C++ function: [slot] void QObject::deleteLater()
.
Schedules this object for deletion.
The object will be deleted when control returns to the event loop. If the event loop is not running when this function is called (e.g. deleteLater() is called on an object before QCoreApplication::exec()), the object will be deleted once the event loop is started. If deleteLater() is called after the main event loop has stopped, the object will not be deleted. Since Qt 4.8, if deleteLater() is called on an object that lives in a thread with no running event loop, the object will be destroyed when the thread finishes.
Note that entering and leaving a new event loop (e.g., by opening a modal dialog) will not perform the deferred deletion; for the object to be deleted, the control must return to the event loop from which deleteLater() was called.
Note: It is safe to call this function more than once; when the first deferred deletion event is delivered, any pending events for the object are removed from the event queue.
sourcepub unsafe fn disconnect_char_q_object_char(
&self,
signal: *const c_char,
receiver: impl CastInto<Ptr<QObject>>,
member: *const c_char
) -> bool
pub unsafe fn disconnect_char_q_object_char( &self, signal: *const c_char, receiver: impl CastInto<Ptr<QObject>>, member: *const c_char ) -> bool
This function overloads disconnect().
Calls C++ function: bool QObject::disconnect(const char* signal = …, const QObject* receiver = …, const char* member = …) const
.
This function overloads disconnect().
Disconnects signal from method of receiver.
A signal-slot connection is removed when either of the objects involved are destroyed.
Note: This function is thread-safe.
sourcepub unsafe fn disconnect_q_object_char(
&self,
receiver: impl CastInto<Ptr<QObject>>,
member: *const c_char
) -> bool
pub unsafe fn disconnect_q_object_char( &self, receiver: impl CastInto<Ptr<QObject>>, member: *const c_char ) -> bool
This function overloads disconnect().
Calls C++ function: bool QObject::disconnect(const QObject* receiver, const char* member = …) const
.
This function overloads disconnect().
Disconnects all signals in this object from receiver's method.
A signal-slot connection is removed when either of the objects involved are destroyed.
sourcepub unsafe fn disconnect_char_q_object(
&self,
signal: *const c_char,
receiver: impl CastInto<Ptr<QObject>>
) -> bool
pub unsafe fn disconnect_char_q_object( &self, signal: *const c_char, receiver: impl CastInto<Ptr<QObject>> ) -> bool
This function overloads disconnect().
Calls C++ function: bool QObject::disconnect(const char* signal = …, const QObject* receiver = …) const
.
This function overloads disconnect().
Disconnects signal from method of receiver.
A signal-slot connection is removed when either of the objects involved are destroyed.
Note: This function is thread-safe.
sourcepub unsafe fn disconnect_char(&self, signal: *const c_char) -> bool
pub unsafe fn disconnect_char(&self, signal: *const c_char) -> bool
This function overloads disconnect().
Calls C++ function: bool QObject::disconnect(const char* signal = …) const
.
This function overloads disconnect().
Disconnects signal from method of receiver.
A signal-slot connection is removed when either of the objects involved are destroyed.
Note: This function is thread-safe.
sourcepub unsafe fn disconnect(&self) -> bool
pub unsafe fn disconnect(&self) -> bool
This function overloads disconnect().
Calls C++ function: bool QObject::disconnect() const
.
This function overloads disconnect().
Disconnects signal from method of receiver.
A signal-slot connection is removed when either of the objects involved are destroyed.
Note: This function is thread-safe.
sourcepub unsafe fn disconnect_q_object(
&self,
receiver: impl CastInto<Ptr<QObject>>
) -> bool
pub unsafe fn disconnect_q_object( &self, receiver: impl CastInto<Ptr<QObject>> ) -> bool
This function overloads disconnect().
Calls C++ function: bool QObject::disconnect(const QObject* receiver) const
.
This function overloads disconnect().
Disconnects all signals in this object from receiver's method.
A signal-slot connection is removed when either of the objects involved are destroyed.
sourcepub unsafe fn dump_object_info_mut(&self)
pub unsafe fn dump_object_info_mut(&self)
Dumps information about signal connections, etc. for this object to the debug output.
Calls C++ function: void QObject::dumpObjectInfo()
.
Dumps information about signal connections, etc. for this object to the debug output.
Note: before Qt 5.9, this function was not const.
See also dumpObjectTree().
sourcepub unsafe fn dump_object_info(&self)
pub unsafe fn dump_object_info(&self)
Dumps information about signal connections, etc. for this object to the debug output.
Calls C++ function: void QObject::dumpObjectInfo() const
.
Dumps information about signal connections, etc. for this object to the debug output.
Note: before Qt 5.9, this function was not const.
See also dumpObjectTree().
sourcepub unsafe fn dump_object_tree_mut(&self)
pub unsafe fn dump_object_tree_mut(&self)
Dumps a tree of children to the debug output.
Calls C++ function: void QObject::dumpObjectTree()
.
Dumps a tree of children to the debug output.
Note: before Qt 5.9, this function was not const.
See also dumpObjectInfo().
sourcepub unsafe fn dump_object_tree(&self)
pub unsafe fn dump_object_tree(&self)
Dumps a tree of children to the debug output.
Calls C++ function: void QObject::dumpObjectTree() const
.
Dumps a tree of children to the debug output.
Note: before Qt 5.9, this function was not const.
See also dumpObjectInfo().
sourcepub unsafe fn dynamic_property_names(&self) -> CppBox<QListOfQByteArray>
pub unsafe fn dynamic_property_names(&self) -> CppBox<QListOfQByteArray>
Returns the names of all properties that were dynamically added to the object using setProperty().
Calls C++ function: QList<QByteArray> QObject::dynamicPropertyNames() const
.
Returns the names of all properties that were dynamically added to the object using setProperty().
This function was introduced in Qt 4.2.
sourcepub unsafe fn eq(&self, p: impl CastInto<Ref<QPointerOfQObject>>) -> bool
pub unsafe fn eq(&self, p: impl CastInto<Ref<QPointerOfQObject>>) -> bool
Returns true
if c1 and c2 are the same Unicode character; otherwise returns false
.
Calls C++ function: bool operator==(QObject* o, const QPointer<QObject>& p)
.
Warning: no exact match found in C++ documentation. Below is the C++ documentation for bool operator==(QChar c1, QChar c2)
:
Returns true
if c1 and c2 are the same Unicode character; otherwise returns false
.
sourcepub unsafe fn event(&self, event: impl CastInto<Ptr<QEvent>>) -> bool
pub unsafe fn event(&self, event: impl CastInto<Ptr<QEvent>>) -> bool
This virtual function receives events to an object and should return true if the event e was recognized and processed.
Calls C++ function: virtual bool QObject::event(QEvent* event)
.
This virtual function receives events to an object and should return true if the event e was recognized and processed.
The event() function can be reimplemented to customize the behavior of an object.
Make sure you call the parent event class implementation for all the events you did not handle.
Example:
class MyClass : public QWidget { Q_OBJECT
public: MyClass(QWidget *parent = 0); ~MyClass();
bool event(QEvent* ev) { if (ev->type() == QEvent::PolishRequest) { // overwrite handling of PolishRequest if any doThings(); return true; } else if (ev->type() == QEvent::Show) { // complement handling of Show if any doThings2(); QWidget::event(ev); return true; } // Make sure the rest of events are handled return QWidget::event(ev); } };
See also installEventFilter(), timerEvent(), QCoreApplication::sendEvent(), and QCoreApplication::postEvent().
sourcepub unsafe fn event_filter(
&self,
watched: impl CastInto<Ptr<QObject>>,
event: impl CastInto<Ptr<QEvent>>
) -> bool
pub unsafe fn event_filter( &self, watched: impl CastInto<Ptr<QObject>>, event: impl CastInto<Ptr<QEvent>> ) -> bool
Filters events if this object has been installed as an event filter for the watched object.
Calls C++ function: virtual bool QObject::eventFilter(QObject* watched, QEvent* event)
.
Filters events if this object has been installed as an event filter for the watched object.
In your reimplementation of this function, if you want to filter the event out, i.e. stop it being handled further, return true; otherwise return false.
Example:
class MainWindow : public QMainWindow { public: MainWindow();
protected: bool eventFilter(QObject obj, QEvent ev);
private: QTextEdit *textEdit; };
MainWindow::MainWindow() { textEdit = new QTextEdit; setCentralWidget(textEdit);
textEdit->installEventFilter(this); }
bool MainWindow::eventFilter(QObject obj, QEvent event) { if (obj == textEdit) { if (event->type() == QEvent::KeyPress) { QKeyEvent keyEvent = static_cast<QKeyEvent>(event); qDebug() << “Ate key press” << keyEvent->key(); return true; } else { return false; } } else { // pass the event on to the parent class return QMainWindow::eventFilter(obj, event); } }
Notice in the example above that unhandled events are passed to the base class's eventFilter() function, since the base class might have reimplemented eventFilter() for its own internal purposes.
Warning: If you delete the receiver object in this function, be sure to return true. Otherwise, Qt will forward the event to the deleted object and the program might crash.
See also installEventFilter().
sourcepub unsafe fn find_child_q_object_2a(
&self,
a_name: impl CastInto<Ref<QString>>,
options: QFlags<FindChildOption>
) -> QPtr<QObject>
pub unsafe fn find_child_q_object_2a( &self, a_name: impl CastInto<Ref<QString>>, options: QFlags<FindChildOption> ) -> QPtr<QObject>
Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.
Calls C++ function: QObject* QObject::findChild<QObject*>(const QString& aName = …, QFlags<Qt::FindChildOption> options = …) const
.
Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.
If there is more than one child matching the search, the most direct ancestor is returned. If there are several direct ancestors, it is undefined which one will be returned. In that case, findChildren() should be used.
This example returns a child QPushButton
of parentWidget
named "button1"
, even if the button isn't a direct child of the parent:
QPushButton button = parentWidget->findChild<QPushButton >(“button1”);
This example returns a QListWidget
child of parentWidget
:
QListWidget list = parentWidget->findChild<QListWidget >();
This example returns a child QPushButton
of parentWidget
(its direct parent) named "button1"
:
QPushButton button = parentWidget->findChild<QPushButton >(“button1”, Qt::FindDirectChildrenOnly);
This example returns a QListWidget
child of parentWidget
, its direct parent:
QListWidget list = parentWidget->findChild<QListWidget >(QString(), Qt::FindDirectChildrenOnly);
See also findChildren().
sourcepub unsafe fn find_child_q_object_1a(
&self,
a_name: impl CastInto<Ref<QString>>
) -> QPtr<QObject>
pub unsafe fn find_child_q_object_1a( &self, a_name: impl CastInto<Ref<QString>> ) -> QPtr<QObject>
Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.
Calls C++ function: QObject* QObject::findChild<QObject*>(const QString& aName = …) const
.
Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.
If there is more than one child matching the search, the most direct ancestor is returned. If there are several direct ancestors, it is undefined which one will be returned. In that case, findChildren() should be used.
This example returns a child QPushButton
of parentWidget
named "button1"
, even if the button isn't a direct child of the parent:
QPushButton button = parentWidget->findChild<QPushButton >(“button1”);
This example returns a QListWidget
child of parentWidget
:
QListWidget list = parentWidget->findChild<QListWidget >();
This example returns a child QPushButton
of parentWidget
(its direct parent) named "button1"
:
QPushButton button = parentWidget->findChild<QPushButton >(“button1”, Qt::FindDirectChildrenOnly);
This example returns a QListWidget
child of parentWidget
, its direct parent:
QListWidget list = parentWidget->findChild<QListWidget >(QString(), Qt::FindDirectChildrenOnly);
See also findChildren().
sourcepub unsafe fn find_child_q_object_0a(&self) -> QPtr<QObject>
pub unsafe fn find_child_q_object_0a(&self) -> QPtr<QObject>
Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.
Calls C++ function: QObject* QObject::findChild<QObject*>() const
.
Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.
If there is more than one child matching the search, the most direct ancestor is returned. If there are several direct ancestors, it is undefined which one will be returned. In that case, findChildren() should be used.
This example returns a child QPushButton
of parentWidget
named "button1"
, even if the button isn't a direct child of the parent:
QPushButton button = parentWidget->findChild<QPushButton >(“button1”);
This example returns a QListWidget
child of parentWidget
:
QListWidget list = parentWidget->findChild<QListWidget >();
This example returns a child QPushButton
of parentWidget
(its direct parent) named "button1"
:
QPushButton button = parentWidget->findChild<QPushButton >(“button1”, Qt::FindDirectChildrenOnly);
This example returns a QListWidget
child of parentWidget
, its direct parent:
QListWidget list = parentWidget->findChild<QListWidget >(QString(), Qt::FindDirectChildrenOnly);
See also findChildren().
sourcepub unsafe fn find_children_q_object_q_string_q_flags_find_child_option(
&self,
a_name: impl CastInto<Ref<QString>>,
options: QFlags<FindChildOption>
) -> CppBox<QListOfQObject>
pub unsafe fn find_children_q_object_q_string_q_flags_find_child_option( &self, a_name: impl CastInto<Ref<QString>>, options: QFlags<FindChildOption> ) -> CppBox<QListOfQObject>
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. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.
Calls C++ function: QList<QObject*> QObject::findChildren<QObject*>(const QString& aName = …, QFlags<Qt::FindChildOption> options = …) 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. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.
The following example shows how to find a list of child QWidget
s of the specified parentWidget
named widgetname
:
QList<QWidget > widgets = parentWidget.findChildren<QWidget >(“widgetname”);
This example returns all QPushButton
s that are children of parentWidget
:
QList<QPushButton > allPButtons = parentWidget.findChildren<QPushButton >();
This example returns all QPushButton
s that are immediate children of parentWidget
:
QList<QPushButton > childButtons = parentWidget.findChildren<QPushButton >(QString(), Qt::FindDirectChildrenOnly);
See also findChild().
sourcepub unsafe fn find_children_q_object_q_reg_exp_q_flags_find_child_option(
&self,
re: impl CastInto<Ref<QRegExp>>,
options: QFlags<FindChildOption>
) -> CppBox<QListOfQObject>
pub unsafe fn find_children_q_object_q_reg_exp_q_flags_find_child_option( &self, re: impl CastInto<Ref<QRegExp>>, options: QFlags<FindChildOption> ) -> CppBox<QListOfQObject>
This function overloads findChildren().
Calls C++ function: QList<QObject*> QObject::findChildren<QObject*>(const QRegExp& re, QFlags<Qt::FindChildOption> options = …) const
.
This function overloads findChildren().
Returns the children of this object that can be cast to type T and that have names matching the regular expression regExp, or an empty list if there are no such objects. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.
sourcepub unsafe fn find_children_q_object_q_regular_expression_q_flags_find_child_option(
&self,
re: impl CastInto<Ref<QRegularExpression>>,
options: QFlags<FindChildOption>
) -> CppBox<QListOfQObject>
pub unsafe fn find_children_q_object_q_regular_expression_q_flags_find_child_option( &self, re: impl CastInto<Ref<QRegularExpression>>, options: QFlags<FindChildOption> ) -> CppBox<QListOfQObject>
This function overloads findChildren().
Calls C++ function: QList<QObject*> QObject::findChildren<QObject*>(const QRegularExpression& re, QFlags<Qt::FindChildOption> options = …) const
.
This function overloads findChildren().
Returns the children of this object that can be cast to type T and that have names matching the regular expression re, or an empty list if there are no such objects. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.
This function was introduced in Qt 5.0.
sourcepub unsafe fn find_children_q_object_q_string(
&self,
a_name: impl CastInto<Ref<QString>>
) -> CppBox<QListOfQObject>
pub unsafe fn find_children_q_object_q_string( &self, a_name: impl CastInto<Ref<QString>> ) -> CppBox<QListOfQObject>
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. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.
Calls C++ function: QList<QObject*> QObject::findChildren<QObject*>(const QString& aName = …) 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. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.
The following example shows how to find a list of child QWidget
s of the specified parentWidget
named widgetname
:
QList<QWidget > widgets = parentWidget.findChildren<QWidget >(“widgetname”);
This example returns all QPushButton
s that are children of parentWidget
:
QList<QPushButton > allPButtons = parentWidget.findChildren<QPushButton >();
This example returns all QPushButton
s that are immediate children of parentWidget
:
QList<QPushButton > childButtons = parentWidget.findChildren<QPushButton >(QString(), Qt::FindDirectChildrenOnly);
See also findChild().
sourcepub unsafe fn find_children_q_object(&self) -> CppBox<QListOfQObject>
pub unsafe fn find_children_q_object(&self) -> CppBox<QListOfQObject>
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. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.
Calls C++ function: QList<QObject*> QObject::findChildren<QObject*>() 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. Omitting the name argument causes all object names to be matched. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.
The following example shows how to find a list of child QWidget
s of the specified parentWidget
named widgetname
:
QList<QWidget > widgets = parentWidget.findChildren<QWidget >(“widgetname”);
This example returns all QPushButton
s that are children of parentWidget
:
QList<QPushButton > allPButtons = parentWidget.findChildren<QPushButton >();
This example returns all QPushButton
s that are immediate children of parentWidget
:
QList<QPushButton > childButtons = parentWidget.findChildren<QPushButton >(QString(), Qt::FindDirectChildrenOnly);
See also findChild().
sourcepub unsafe fn find_children_q_object_q_reg_exp(
&self,
re: impl CastInto<Ref<QRegExp>>
) -> CppBox<QListOfQObject>
pub unsafe fn find_children_q_object_q_reg_exp( &self, re: impl CastInto<Ref<QRegExp>> ) -> CppBox<QListOfQObject>
This function overloads findChildren().
Calls C++ function: QList<QObject*> QObject::findChildren<QObject*>(const QRegExp& re) const
.
This function overloads findChildren().
Returns the children of this object that can be cast to type T and that have names matching the regular expression regExp, or an empty list if there are no such objects. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.
sourcepub unsafe fn find_children_q_object_q_regular_expression(
&self,
re: impl CastInto<Ref<QRegularExpression>>
) -> CppBox<QListOfQObject>
pub unsafe fn find_children_q_object_q_regular_expression( &self, re: impl CastInto<Ref<QRegularExpression>> ) -> CppBox<QListOfQObject>
This function overloads findChildren().
Calls C++ function: QList<QObject*> QObject::findChildren<QObject*>(const QRegularExpression& re) const
.
This function overloads findChildren().
Returns the children of this object that can be cast to type T and that have names matching the regular expression re, or an empty list if there are no such objects. The search is performed recursively, unless options specifies the option FindDirectChildrenOnly.
This function was introduced in Qt 5.0.
sourcepub unsafe fn inherits(&self, classname: *const c_char) -> bool
pub unsafe fn inherits(&self, classname: *const c_char) -> bool
Returns true
if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false
.
Calls C++ function: bool QObject::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
.
A class is considered to inherit itself.
Example:
QTimer *timer = new QTimer; // QTimer inherits QObject timer->inherits(“QTimer”); // returns true timer->inherits(“QObject”); // returns true timer->inherits(“QAbstractButton”); // returns false
// QVBoxLayout inherits QObject and QLayoutItem QVBoxLayout *layout = new QVBoxLayout; layout->inherits(“QObject”); // returns true layout->inherits(“QLayoutItem”); // returns true (even though QLayoutItem is not a QObject)
If you need to determine whether an object is an instance of a particular class for the purpose of casting it, consider using qobject_cast<Type *>(object) instead.
See also metaObject() and qobject_cast().
sourcepub unsafe fn install_event_filter(
&self,
filter_obj: impl CastInto<Ptr<QObject>>
)
pub unsafe fn install_event_filter( &self, filter_obj: impl CastInto<Ptr<QObject>> )
Installs an event filter filterObj on this object. For example:
Calls C++ function: void QObject::installEventFilter(QObject* filterObj)
.
Installs an event filter filterObj on this object. For example:
monitoredObj->installEventFilter(filterObj);
An event filter is an object that receives all events that are sent to this object. The filter can either stop the event or forward it to this object. The event filter filterObj receives events via its eventFilter() function. The eventFilter() function must return true if the event should be filtered, (i.e. stopped); otherwise it must return false.
If multiple event filters are installed on a single object, the filter that was installed last is activated first.
Here's a KeyPressEater
class that eats the key presses of its monitored objects:
class KeyPressEater : public QObject { Q_OBJECT ...
protected: bool eventFilter(QObject obj, QEvent event); };
bool KeyPressEater::eventFilter(QObject obj, QEvent event) { if (event->type() == QEvent::KeyPress) { QKeyEvent keyEvent = static_cast<QKeyEvent >(event); qDebug(“Ate key press %d”, keyEvent->key()); return true; } else { // standard event processing return QObject::eventFilter(obj, event); } }
And here's how to install it on two widgets:
KeyPressEater keyPressEater = new KeyPressEater(this); QPushButton pushButton = new QPushButton(this); QListView *listView = new QListView(this);
pushButton->installEventFilter(keyPressEater); listView->installEventFilter(keyPressEater);
The QShortcut class, for example, uses this technique to intercept shortcut key presses.
Warning: If you delete the receiver object in your eventFilter() function, be sure to return true. If you return false, Qt sends the event to the deleted object and the program will crash.
Note that the filtering object must be in the same thread as this object. If filterObj is in a different thread, this function does nothing. If either filterObj or this object are moved to a different thread after calling this function, the event filter will not be called until both objects have the same thread affinity again (it is not removed).
See also removeEventFilter(), eventFilter(), and event().
sourcepub unsafe fn is_widget_type(&self) -> bool
pub unsafe fn is_widget_type(&self) -> bool
Returns true
if the object is a widget; otherwise returns false
.
Calls C++ function: bool QObject::isWidgetType() const
.
Returns true
if the object is a widget; otherwise returns false
.
Calling this function is equivalent to calling inherits("QWidget")
, except that it is much faster.
sourcepub unsafe fn is_window_type(&self) -> bool
pub unsafe fn is_window_type(&self) -> bool
Returns true
if the object is a window; otherwise returns false
.
Calls C++ function: bool QObject::isWindowType() const
.
Returns true
if the object is a window; otherwise returns false
.
Calling this function is equivalent to calling inherits("QWindow")
, except that it is much faster.
sourcepub unsafe fn kill_timer(&self, id: c_int)
pub unsafe fn kill_timer(&self, id: c_int)
Kills the timer with timer identifier, id.
Calls C++ function: void QObject::killTimer(int id)
.
Kills the timer with timer identifier, id.
The timer identifier is returned by startTimer() when a timer event is started.
See also timerEvent() and startTimer().
sourcepub unsafe fn meta_object(&self) -> Ptr<QMetaObject>
pub unsafe fn meta_object(&self) -> Ptr<QMetaObject>
Returns a pointer to the meta-object of this object.
Calls C++ function: virtual const QMetaObject* QObject::metaObject() const
.
Returns a pointer to the meta-object of this object.
A meta-object contains information about a class that inherits QObject, e.g. class name, superclass name, properties, signals and slots. Every QObject subclass that contains the Q_OBJECT macro will have a meta-object.
The meta-object information is required by the signal/slot connection mechanism and the property system. The inherits() function also makes use of the meta-object.
If you have no pointer to an actual object instance but still want to access the meta-object of a class, you can use staticMetaObject.
Example:
QObject *obj = new QPushButton; obj->metaObject()->className(); // returns “QPushButton”
QPushButton::staticMetaObject.className(); // returns “QPushButton”
See also staticMetaObject.
sourcepub unsafe fn move_to_thread(&self, thread: impl CastInto<Ptr<QThread>>)
pub unsafe fn move_to_thread(&self, thread: impl CastInto<Ptr<QThread>>)
Changes the thread affinity for this object and its children. The object cannot be moved if it has a parent. Event processing will continue in the targetThread.
Calls C++ function: void QObject::moveToThread(QThread* thread)
.
Changes the thread affinity for this object and its children. The object cannot be moved if it has a parent. Event processing will continue in the targetThread.
To move an object to the main thread, use QApplication::instance() to retrieve a pointer to the current application, and then use QApplication::thread() to retrieve the thread in which the application lives. For example:
myObject->moveToThread(QApplication::instance()->thread());
If targetThread is zero, all event processing for this object and its children stops.
Note that all active timers for the object will be reset. The timers are first stopped in the current thread and restarted (with the same interval) in the targetThread. As a result, constantly moving an object between threads can postpone timer events indefinitely.
A QEvent::ThreadChange event is sent to this object just before the thread affinity is changed. You can handle this event to perform any special processing. Note that any new events that are posted to this object will be handled in the targetThread.
Warning: This function is not thread-safe; the current thread must be same as the current thread affinity. In other words, this function can only "push" an object from the current thread to another thread, it cannot "pull" an object from any arbitrary thread to the current thread.
See also thread().
sourcepub unsafe fn object_name(&self) -> CppBox<QString>
pub unsafe fn object_name(&self) -> CppBox<QString>
This property holds the name of this object
Calls C++ function: QString QObject::objectName() const
.
This property holds the name of this object
You can find an object by name (and type) using findChild(). You can find a set of objects with findChildren().
qDebug(“MyClass::setPrecision(): (%s) invalid precision %f”, qPrintable(objectName()), newPrecision);
By default, this property contains an empty string.
Access functions:
QString | objectName() const |
void | setObjectName(const QString &name) |
Notifier signal:
void | objectNameChanged(const QString &objectName) | [see note below] |
Note: This is a private signal. It can be used in signal connections but cannot be emitted by the user.
See also metaObject() and QMetaObject::className().
sourcepub unsafe fn parent(&self) -> QPtr<QObject>
pub unsafe fn parent(&self) -> QPtr<QObject>
Returns a pointer to the parent object.
Calls C++ function: QObject* QObject::parent() const
.
sourcepub unsafe fn property(&self, name: *const c_char) -> CppBox<QVariant>
pub unsafe fn property(&self, name: *const c_char) -> CppBox<QVariant>
Returns the value of the object's name property.
Calls C++ function: QVariant QObject::property(const char* name) const
.
Returns the value of the object’s name property.
If no such property exists, the returned variant is invalid.
Information about all available properties is provided through the metaObject() and dynamicPropertyNames().
See also setProperty(), QVariant::isValid(), metaObject(), and dynamicPropertyNames().
sourcepub unsafe fn qt_metacall(
&self,
arg1: Call,
arg2: c_int,
arg3: *mut *mut c_void
) -> c_int
pub unsafe fn qt_metacall( &self, arg1: Call, arg2: c_int, arg3: *mut *mut c_void ) -> c_int
Calls C++ function: virtual int QObject::qt_metacall(QMetaObject::Call arg1, int arg2, void** arg3)
.
sourcepub unsafe fn qt_metacast(&self, arg1: *const c_char) -> *mut c_void
pub unsafe fn qt_metacast(&self, arg1: *const c_char) -> *mut c_void
Calls C++ function: virtual void* QObject::qt_metacast(const char* arg1)
.
sourcepub unsafe fn remove_event_filter(&self, obj: impl CastInto<Ptr<QObject>>)
pub unsafe fn remove_event_filter(&self, obj: impl CastInto<Ptr<QObject>>)
Removes an event filter object obj from this object. The request is ignored if such an event filter has not been installed.
Calls C++ function: void QObject::removeEventFilter(QObject* obj)
.
Removes an event filter object obj from this object. The request is ignored if such an event filter has not been installed.
All event filters for this object are automatically removed when this object is destroyed.
It is always safe to remove an event filter, even during event filter activation (i.e. from the eventFilter() function).
See also installEventFilter(), eventFilter(), and event().
sourcepub unsafe fn set_object_name(&self, name: impl CastInto<Ref<QString>>)
pub unsafe fn set_object_name(&self, name: impl CastInto<Ref<QString>>)
This property holds the name of this object
Calls C++ function: void QObject::setObjectName(const QString& name)
.
This property holds the name of this object
You can find an object by name (and type) using findChild(). You can find a set of objects with findChildren().
qDebug(“MyClass::setPrecision(): (%s) invalid precision %f”, qPrintable(objectName()), newPrecision);
By default, this property contains an empty string.
Access functions:
QString | objectName() const |
void | setObjectName(const QString &name) |
Notifier signal:
void | objectNameChanged(const QString &objectName) | [see note below] |
Note: This is a private signal. It can be used in signal connections but cannot be emitted by the user.
See also metaObject() and QMetaObject::className().
sourcepub unsafe fn set_parent(&self, parent: impl CastInto<Ptr<QObject>>)
pub unsafe fn set_parent(&self, parent: impl CastInto<Ptr<QObject>>)
Makes the object a child of parent.
Calls C++ function: void QObject::setParent(QObject* parent)
.
sourcepub unsafe fn set_property(
&self,
name: *const c_char,
value: impl CastInto<Ref<QVariant>>
) -> bool
pub unsafe fn set_property( &self, name: *const c_char, value: impl CastInto<Ref<QVariant>> ) -> bool
Sets the value of the object's name property to value.
Calls C++ function: bool QObject::setProperty(const char* name, const QVariant& value)
.
Sets the value of the object’s name property to value.
If the property is defined in the class using Q_PROPERTY then true is returned on success and false otherwise. If the property is not defined using Q_PROPERTY, and therefore not listed in the meta-object, it is added as a dynamic property and false is returned.
Information about all available properties is provided through the metaObject() and dynamicPropertyNames().
Dynamic properties can be queried again using property() and can be removed by setting the property value to an invalid QVariant. Changing the value of a dynamic property causes a QDynamicPropertyChangeEvent to be sent to the object.
Note: Dynamic properties starting with "_q_" are reserved for internal purposes.
See also property(), metaObject(), dynamicPropertyNames(), and QMetaProperty::write().
sourcepub unsafe fn signals_blocked(&self) -> bool
pub unsafe fn signals_blocked(&self) -> bool
Returns true
if signals are blocked; otherwise returns false
.
Calls C++ function: bool QObject::signalsBlocked() const
.
Returns true
if signals are blocked; otherwise returns false
.
Signals are not blocked by default.
See also blockSignals() and QSignalBlocker.
sourcepub unsafe fn start_timer_2a(
&self,
interval: c_int,
timer_type: TimerType
) -> c_int
pub unsafe fn start_timer_2a( &self, interval: c_int, timer_type: TimerType ) -> c_int
Starts a timer and returns a timer identifier, or returns zero if it could not start a timer.
Calls C++ function: int QObject::startTimer(int interval, Qt::TimerType timerType = …)
.
Starts a timer and returns a timer identifier, or returns zero if it could not start a timer.
A timer event will occur every interval milliseconds until killTimer() is called. If interval is 0, then the timer event occurs once every time there are no more window system events to process.
The virtual timerEvent() function is called with the QTimerEvent event parameter class when a timer event occurs. Reimplement this function to get timer events.
If multiple timers are running, the QTimerEvent::timerId() can be used to find out which timer was activated.
Example:
class MyObject : public QObject { Q_OBJECT
public: MyObject(QObject *parent = 0);
protected: void timerEvent(QTimerEvent *event); };
MyObject::MyObject(QObject *parent) : QObject(parent) { startTimer(50); // 50-millisecond timer startTimer(1000); // 1-second timer startTimer(60000); // 1-minute timer
using namespace std::chrono; startTimer(milliseconds(50)); startTimer(seconds(1)); startTimer(minutes(1));
// since C++14 we can use std::chrono::duration literals, e.g.: startTimer(100ms); startTimer(5s); startTimer(2min); startTimer(1h); }
void MyObject::timerEvent(QTimerEvent *event) { qDebug() << “Timer ID:” << event->timerId(); }
Note that QTimer's accuracy depends on the underlying operating system and hardware. The timerType argument allows you to customize the accuracy of the timer. See Qt::TimerType for information on the different timer types. Most platforms support an accuracy of 20 milliseconds; some provide more. If Qt is unable to deliver the requested number of timer events, it will silently discard some.
The QTimer class provides a high-level programming interface with single-shot timers and timer signals instead of events. There is also a QBasicTimer class that is more lightweight than QTimer and less clumsy than using timer IDs directly.
See also timerEvent(), killTimer(), and QTimer::singleShot().
sourcepub unsafe fn start_timer_1a(&self, interval: c_int) -> c_int
pub unsafe fn start_timer_1a(&self, interval: c_int) -> c_int
Starts a timer and returns a timer identifier, or returns zero if it could not start a timer.
Calls C++ function: int QObject::startTimer(int interval)
.
Starts a timer and returns a timer identifier, or returns zero if it could not start a timer.
A timer event will occur every interval milliseconds until killTimer() is called. If interval is 0, then the timer event occurs once every time there are no more window system events to process.
The virtual timerEvent() function is called with the QTimerEvent event parameter class when a timer event occurs. Reimplement this function to get timer events.
If multiple timers are running, the QTimerEvent::timerId() can be used to find out which timer was activated.
Example:
class MyObject : public QObject { Q_OBJECT
public: MyObject(QObject *parent = 0);
protected: void timerEvent(QTimerEvent *event); };
MyObject::MyObject(QObject *parent) : QObject(parent) { startTimer(50); // 50-millisecond timer startTimer(1000); // 1-second timer startTimer(60000); // 1-minute timer
using namespace std::chrono; startTimer(milliseconds(50)); startTimer(seconds(1)); startTimer(minutes(1));
// since C++14 we can use std::chrono::duration literals, e.g.: startTimer(100ms); startTimer(5s); startTimer(2min); startTimer(1h); }
void MyObject::timerEvent(QTimerEvent *event) { qDebug() << “Timer ID:” << event->timerId(); }
Note that QTimer's accuracy depends on the underlying operating system and hardware. The timerType argument allows you to customize the accuracy of the timer. See Qt::TimerType for information on the different timer types. Most platforms support an accuracy of 20 milliseconds; some provide more. If Qt is unable to deliver the requested number of timer events, it will silently discard some.
The QTimer class provides a high-level programming interface with single-shot timers and timer signals instead of events. There is also a QBasicTimer class that is more lightweight than QTimer and less clumsy than using timer IDs directly.
See also timerEvent(), killTimer(), and QTimer::singleShot().
sourcepub unsafe fn thread(&self) -> QPtr<QThread>
pub unsafe fn thread(&self) -> QPtr<QThread>
Returns the thread in which the object lives.
Calls C++ function: QThread* QObject::thread() const
.
Returns the thread in which the object lives.
See also moveToThread().
Trait Implementations§
source§impl CppDeletable for QSaveFile
impl CppDeletable for QSaveFile
source§impl Deref for QSaveFile
impl Deref for QSaveFile
source§fn deref(&self) -> &QFileDevice
fn deref(&self) -> &QFileDevice
Calls C++ function: QFileDevice* static_cast<QFileDevice*>(QSaveFile* ptr)
.
§type Target = QFileDevice
type Target = QFileDevice
source§impl DynamicCast<QSaveFile> for QFileDevice
impl DynamicCast<QSaveFile> for QFileDevice
source§unsafe fn dynamic_cast(ptr: Ptr<QFileDevice>) -> Ptr<QSaveFile>
unsafe fn dynamic_cast(ptr: Ptr<QFileDevice>) -> Ptr<QSaveFile>
Calls C++ function: QSaveFile* dynamic_cast<QSaveFile*>(QFileDevice* ptr)
.
source§impl DynamicCast<QSaveFile> for QIODevice
impl DynamicCast<QSaveFile> for QIODevice
source§impl DynamicCast<QSaveFile> for QObject
impl DynamicCast<QSaveFile> for QObject
source§impl StaticDowncast<QSaveFile> for QFileDevice
impl StaticDowncast<QSaveFile> for QFileDevice
source§unsafe fn static_downcast(ptr: Ptr<QFileDevice>) -> Ptr<QSaveFile>
unsafe fn static_downcast(ptr: Ptr<QFileDevice>) -> Ptr<QSaveFile>
Calls C++ function: QSaveFile* static_cast<QSaveFile*>(QFileDevice* ptr)
.
source§impl StaticDowncast<QSaveFile> for QIODevice
impl StaticDowncast<QSaveFile> for QIODevice
source§impl StaticDowncast<QSaveFile> for QObject
impl StaticDowncast<QSaveFile> for QObject
source§impl StaticUpcast<QFileDevice> for QSaveFile
impl StaticUpcast<QFileDevice> for QSaveFile
source§unsafe fn static_upcast(ptr: Ptr<QSaveFile>) -> Ptr<QFileDevice>
unsafe fn static_upcast(ptr: Ptr<QSaveFile>) -> Ptr<QFileDevice>
Calls C++ function: QFileDevice* static_cast<QFileDevice*>(QSaveFile* ptr)
.