The stack frame

The stack frame is a term you may have come across. It is the amount of memory allocated to a function, which is used to store all of the local variables and function parameters. In the following snippet, the stack frame will be large enough to store the two int values and the single float32 type:

    fn main() 
    { 
        let a = 10; 
        let b = 20; 
        let pi = 3.14f32; 
    } 

Once main has exited, the stack frame allocated on entry will be released. The beauty of both the allocation and deallocation is that they are carried out without the user needing to do anything. The amount of memory can also be computed ahead of time, as the compiler knows which local variables are in use. This, again, gives a speed increase.

For every positive, there is a downside: the values stored only exist for the lifetime of the method.