Threading and process creation

Executing multiple tasks simultaneously can be accomplished by asking the operating system to create additional threads (or even new processes). This is a common task in system programming, and there are numerous system calls to get the job done.

A process is a unit of execution that has a set of resources assigned to it (for example, memory, file descriptors, and so on.) Each application is made up of at least one process, but they can contain more than one (for example, a shell is an application that is specifically designed to run several child processes).

Each process is scheduled by the operating system to execute for a limited amount of time before the next process is given access to the CPU, and this cycle continues as needed.

Threads are like processes, but they share the same resources as other threads of the same process. Threads provide an application with an opportunity to create tasks that are capable of executing in parallel, without the need for inter-process communication methods. In Chapter 12, Learning to Program POSIX and C++ Threads, we will learn how to program threads using both POSIX and C++ APIs.