Locking Constructs

Construct	Purpose	Cross-Process?	Speed
lock	Ensures just one thread can access a resource, or section of code.	no	fast
Mutex	Ensures just one thread can access a resource, or section of code. Can be used to prevent multiple instances of an application from starting.	yes	moderate
Semaphore	Ensures not more than a specified number of threads can access a resource, or section of code.	yes	moderate