C# 4.0 Unleashed

Locking on Objects

Lots of real-world software doesn’t have a single thread of execution. To execute multiple tasks at a time, threads or abstractions thereof (such as tasks in .NET 4.0) are used. It’s the responsibility of the underlying operating system scheduler or a runtime facility to let units of execution get a turn at making progress. Concepts such as context switches, thread pool management, and so on directly relate to this.

What’s of more interest to us in this context is the problem of different threads accessing the same resource simultaneously. This gives rise to potential issues with regard to consistency of state. To avoid going too abstract here, let’s make things very concrete by presenting a Counter class that maintains a ...