A slot is an area in between face-off circles in the offensive zone. This is where a defenseman can take a shot or redirect a puck. There are two different types of slots: low and high. Low slots are right in front of the goaltender, while high slots are in the middle of the ice above the face-off circles.
Slots are used in many applications. Some demo slot pragmatic machines are activated by a lever. They accept paper tickets with barcodes. Others are purely electronic. Modern slot machines have microprocessors. The machine then uses a random number generator to determine the winning combination. These combinations earn credits based on the pay table.
Slots are also used to receive signals. For example, a vending machine may have a slot for a coin. Similarly, air traffic controllers at busy airports use slots to prevent repeated delays.
Using slots to emit signals is an effective technique for improving productivity. Unlike calling receivers directly, using a slot is much less costly. In addition, the overhead of locating a connection object is significantly smaller. However, the slot does not know if it has connected to a signal.
To connect a signal to a slot, use the QObject::connect method. It will connect the signal to the slot using both the SIGNAL and SLOT macros. As a result, a lambda will be disconnected when the sender or context is destroyed.
To use slots to receive signals, the signals must be emitted from a class that defines a signal. If the signal is emitted from a class that is not defined, the slot will be invoked in an unrelated class.