Struct qt_core::ConnectionType
source · pub struct ConnectionType(/* private fields */);
Expand description
This enum describes the types of connection that can be used between signals and slots. In particular, it determines whether a particular signal is delivered to a slot immediately or queued for delivery at a later time.
C++ enum: Qt::ConnectionType
.
This enum describes the types of connection that can be used between signals and slots. In particular, it determines whether a particular signal is delivered to a slot immediately or queued for delivery at a later time.
With queued connections, the parameters must be of types that are known to Qt's meta-object system, because Qt needs to copy the arguments to store them in an event behind the scenes. If you try to use a queued connection and get the error message:
QObject::connect: Cannot queue arguments of type ‘MyType’
Call qRegisterMetaType() to register the data type before you establish the connection.
When using signals and slots with multiple threads, see Signals and Slots Across Threads.
See also Thread Support in Qt, QObject::connect(), qRegisterMetaType(), and Q_DECLARE_METATYPE().
Implementations§
source§impl ConnectionType
impl ConnectionType
sourcepub const AutoConnection: ConnectionType = _
pub const AutoConnection: ConnectionType = _
(Default) If the receiver lives in the thread that emits the signal, Qt::DirectConnection is used. Otherwise, Qt::QueuedConnection is used. The connection type is determined when the signal is emitted. (C++ enum variant: AutoConnection = 0
)
sourcepub const DirectConnection: ConnectionType = _
pub const DirectConnection: ConnectionType = _
The slot is invoked immediately when the signal is emitted. The slot is executed in the signalling thread. (C++ enum variant: DirectConnection = 1
)
sourcepub const QueuedConnection: ConnectionType = _
pub const QueuedConnection: ConnectionType = _
The slot is invoked when control returns to the event loop of the receiver’s thread. The slot is executed in the receiver’s thread. (C++ enum variant: QueuedConnection = 2
)
sourcepub const BlockingQueuedConnection: ConnectionType = _
pub const BlockingQueuedConnection: ConnectionType = _
Same as Qt::QueuedConnection, except that the signalling thread blocks until the slot returns. This connection must not be used if the receiver lives in the signalling thread, or else the application will deadlock. (C++ enum variant: BlockingQueuedConnection = 3
)
sourcepub const UniqueConnection: ConnectionType = _
pub const UniqueConnection: ConnectionType = _
This is a flag that can be combined with any one of the above connection types, using a bitwise OR. When Qt::UniqueConnection is set, QObject::connect() will fail if the connection already exists (i.e. if the same signal is already connected to the same slot for the same pair of objects). This flag was introduced in Qt 4.6. (C++ enum variant: UniqueConnection = 128
)
Trait Implementations§
source§impl Clone for ConnectionType
impl Clone for ConnectionType
source§fn clone(&self) -> ConnectionType
fn clone(&self) -> ConnectionType
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for ConnectionType
impl Debug for ConnectionType
source§impl From<ConnectionType> for c_int
impl From<ConnectionType> for c_int
source§fn from(value: ConnectionType) -> Self
fn from(value: ConnectionType) -> Self
source§impl From<i32> for ConnectionType
impl From<i32> for ConnectionType
source§impl PartialEq for ConnectionType
impl PartialEq for ConnectionType
source§fn eq(&self, other: &ConnectionType) -> bool
fn eq(&self, other: &ConnectionType) -> bool
self
and other
values to be equal, and is used
by ==
.