Process execution APIs

Every program is executed as a process. Before we have a process, we just have an executable binary file that contains some memory segments and probably lots of machine-level instructions. Conversely, every process is an individual instance of a program being executed. Therefore, a single compiled program (or an executable binary file) can be executed multiple times through different processes. In fact, that's why our focus is on the processes in this chapter, rather than upon the programs themselves.

In two previous chapters, we talked about threads in single-process software, but to follow our objective in this chapter, we are going to be talking about software with multiple processes. But first, we need to know how, and by using which API, a new process can be spawned.

Note that our main focus is on executing processes in Unix-like operating systems since all of them follow the Unix onion architecture and expose very well-known and similar...