Exit (system call)

OS/360 was used on most IBM mainframe computers beginning in 1966, including computers used by the Apollo program.

Exit system call.

- Exit (system call)

22 related topics

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Resource management (computing)

In computer programming, resource management refers to techniques for managing resources (components with limited availability).

Ada Lovelace, whose notes added to the end of Luigi Menabrea's paper included the first algorithm designed for processing by an Analytical Engine. She is often recognized as history's first computer programmer.

On many systems, the operating system reclaims resources after the process makes the exit system call.

Parent process

Process that has created one or more child processes.

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When a process terminates its execution, either by calling exit (even if implicitly, by executing a return command from the main function) or by receiving a signal that causes it to terminate abruptly, the operating system releases most of the resources and information related to that process, but still keeps the data about resource utilization and the termination status code, because a parent process might be interested in knowing if that child executed successfully (by using standard functions to decode the termination status code) and the amount of system resources it consumed during its execution.

Exit status

Small number passed from a child process to a parent process (or caller) when it has finished executing a specific procedure or delegated task.

Ada Lovelace, whose notes added to the end of Luigi Menabrea's paper included the first algorithm designed for processing by an Analytical Engine. She is often recognized as history's first computer programmer.

When the child finishes executing, it exits by calling the exit system call.

Child process

Process created by another process .

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The SIGCHLD signal is sent to the parent of a child process when it exits, is interrupted, or resumes after being interrupted.

Signal (IPC)

Signals are standardized messages sent to a running program to trigger specific behavior, such as quitting or error handling.

Lovelace's description from Note G.

The SIGCHLD signal is sent to a process when a child process terminates, is interrupted, or resumes after being interrupted. One common usage of the signal is to instruct the operating system to clean up the resources used by a child process after its termination without an explicit call to the system call.

Process state

In a multitasking computer system, processes may occupy a variety of states.

The various process states, displayed in a state diagram, with arrows indicating possible transitions between states - as can be seen some processes are stored in main memory (yellow), and some are stored in secondary memory (green).

A process may be terminated, either from the "running" state by completing its execution or by explicitly being killed.

Wait (system call)

In computer operating systems, a process (or task) may wait on another process to complete its execution.

A human computer, with microscope and calculator, 1952

An operating system may provide variations of the wait call that allow a process to wait for any of its child processes to exit, or to wait for a single specific child process (identified by its process ID) to exit.

Orphan process

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An orphan process is a computer process whose parent process has finished or terminated, though it remains running itself.

ASCII

Character encoding standard for electronic communication.

ASCII chart from a pre-1972 printer manual
ASCII (1963). Control pictures of equivalent controls are shown where they exist, or a grey dot otherwise.

In graphical user interface (GUI) and windowing systems, ESC generally causes an application to abort its current operation or to exit (terminate) altogether.

Statement (computer science)

Syntactic unit of an imperative programming language that expresses some action to be carried out.

Ada Lovelace, whose notes added to the end of Luigi Menabrea's paper included the first algorithm designed for processing by an Analytical Engine. She is often recognized as history's first computer programmer.

stop/halt/exit