The exit status or return code of a process in computer programming is a small number passed from a child process (or callee) to a parent process (or caller) when it has finished executing a specific procedure or delegated task. In DOS, this may be referred to as an errorlevel.
When computer programs are executed, the operating system creates an abstract entity called a process in which the book-keeping for that program is maintained. In multitasking operating systems such as Unix or Linux, new processes can be created by active processes. The process that spawns another is called a parent process, while those created are child processes. Child processes run concurrently with the parent process. The technique of spawning child processes is used to delegate some work to a child process when there is no reason to stop the execution of the parent. When the child finishes executing, it exits by calling the exit system call. This system call facilitates passing the exit status code back to the parent, which can retrieve this value using the wait system call.
Read more about Exit Status: Semantics
Famous quotes containing the words exit and/or status:
“There is no exit from the circle of one’s beliefs.”
—Keith Lehrer (b. 1936)
“What is clear is that Christianity directed increased attention to childhood. For the first time in history it seemed important to decide what the moral status of children was. In the midst of this sometimes excessive concern, a new sympathy for children was promoted. Sometimes this meant criticizing adults. . . . So far as parents were put on the defensive in this way, the beginning of the Christian era marks a revolution in the child’s status.”
—C. John Sommerville (20th century)