What Is a Slot?
A slot is a place or time where something happens. Using time slots to establish important deadlines can help organize multiple tasks and support consistency throughout workflow. For example, professional organizations may use scheduling software to set milestones that support project objectives. Slot-based schedules can also help track progress and ensure teams are making progress towards meeting business goals.
In a slot machine, the player inserts cash or, in ticket-in, ticket-out machines, a paper ticket with a barcode, into a designated slot to activate the machine. The machine then spins reels or, in video games, displays symbols on a screen and pays credits when the winning combination lines up. The amount of credits won varies depending on the type and configuration of the machine. Most online slot games have a theme, and the symbols and bonus features align with that theme.
When a slot is used, the compiler automatically checks that the signal’s arguments match the function pointers in the slot. This is a benefit of the slot mechanism that can’t be achieved with callbacks, where the arguments are passed via a pointer and checked manually. On the other hand, slots are a little slower because they require an extra step of emitting a signal that connects to multiple receivers. This involves iterating over all connected signals and slots and checking that the signal and receivers are all still alive (and that they don’t have dependencies on each other). This process is also much slower than calling a function directly.