Child process¶

Category: Units of execution · Status: stub · Lessons: chapter 08, Processes (planned)

One line: A process started by another program, which can pass it input, read its output, wait for it and learn how it ended.

Also called: subprocess, spawn, fork and exec.

How it connects¶

flowchart LR
  n_subprocess["Child process"]
  n_process["Process"]
  n_subprocess -->|is a| n_process
  classDef center stroke-width:3px
  class n_subprocess center
  classDef outside stroke-dasharray: 4 3
  class n_process outside

Is a kind of: Process
See also: Inter-process communication

In each language¶


Rust	`std::process::Command` ↗
Go	`os/exec` ↗
C	`posix_spawn` ↗, or `fork` then `exec`, and `waitpid` ↗ for the exit status
Java	`ProcessBuilder` ↗
Python	`subprocess` ↗, and asyncio subprocesses ↗ for use inside an event loop
JavaScript	Node's `child_process` ↗

Where to read more¶

In this library: Who waits when main returns?
In the books: Python Concurrency with asyncio, Matthew Fowler — ch. 13, 'Managing subprocesses'
In the books: Python Asyncio Jump-Start, Jason Brownlee — ch. 6, 'Subprocesses and Streams'
In the books: JavaScript Concurrency, Adam Boduch — ch. 9, 'Advanced NodeJS Concurrency' → 'Child Processes'
In the books: Effective Python, Brett Slatkin — ch. 7, 'Concurrency and Parallelism' → 'Item 52: Use subprocess to Manage Child Processes'
In the books: Python in a Nutshell, Alex Martelli, Anna Ravenscroft, Steve Holden — ch. 14, 'Threads and Processes' → 'Running Other Programs'
Reference: Wikipedia: Child process ↗