Struct ConnectionType

pub struct ConnectionType(/* private fields */);

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.

C++ documentation:

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

impl ConnectionType

pub fn to_int(&self) -> c_int

impl 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)

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)

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)

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)

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

impl Clone for ConnectionType

fn clone(&self) -> ConnectionType

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ConnectionType

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<ConnectionType> for c_int

fn from(value: ConnectionType) -> Self

Converts to this type from the input type.

impl From<i32> for ConnectionType

fn from(value: c_int) -> Self

Converts to this type from the input type.

impl PartialEq for ConnectionType

fn eq(&self, other: &ConnectionType) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for ConnectionType

impl Eq for ConnectionType

impl StructuralPartialEq for ConnectionType