BASIC THREAD CONCEPTS

Multithreaded programming is substantially more complex than programming with a single thread. Creation and destruction of threads must be managed; most of the complexity stems from coordinating access to resources shared between the threads. When access is not appropriately controlled, multithreaded programs can exhibit several classes of bugs not encountered in single-threaded applications.

Threads

A thread is the fundamental unit of execution within an application: a running application consists of at least one thread. Each thread has its own stack and runs independently from the application’s other threads. By default, threads share their resources, such as file handles or memory. Problems can occur when access to shared resources is not properly controlled. Data corruption is a common side effect of having two threads simultaneously write data to the same block of memory, for example.

Threads can be implemented in different ways. On most systems, threads...