Mastering Delphi Programming: A Complete Reference Guide

Shared data with built-in locking

Sometimes you don't need to implement an additional locking mechanism because Delphi already does that for you. The runtime library contains three such data structures—TThreadList, TThreadList<T>, and TThreadedQueue<T>. The first one can be found in the System.Classes unit, while the other two live in System.Generics.Collections.

Both variants of TThreadList work the same. They don't expose the normal list-management functions (such as Add, Remove, Items[], and so on). Instead of that, they implement the LockList function, which uses TMonitor to acquire access to an internal TList (or TList<T>) object and returns that object. To release access to this list, the program has to call the UnlockList function. ...