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Detached thread

Category: Units of execution · Status: stub · Lessons: chapter 01, Threads

One line: A thread nobody will join: its result is unreachable, its end is unobserved, and whatever it borrowed must outlive it by some other argument.

Also called: detach, fire and forget.

How it connects

flowchart LR
  n_detached_thread["Detached thread"]
  n_task_leak["Leaked tasks"]
  n_scoped_thread["Scoped thread"]
  n_thread["Thread"]
  n_detached_thread -->|can cause| n_task_leak
  n_detached_thread ---|vs| n_scoped_thread
  n_detached_thread -->|is a| n_thread
  classDef center stroke-width:3px
  class n_detached_thread center
  classDef outside stroke-dasharray: 4 3
  class n_task_leak,n_scoped_thread,n_thread outside

In each language
Rust Dropping a JoinHandle ↗ detaches its thread; the 'static bound on thread::spawn ↗ is what makes that safe
Go Every goroutine is detached: a go statement ↗ yields no handle, and a sync.WaitGroup or a channel is how a program waits
C pthread_detach ↗ marks a thread unjoinable and lets its storage be reclaimed as it ends
C++ std::thread::detach ↗; a std::thread destroyed while still joinable calls std::terminate ↗
Python Thread(daemon=True) ↗ is not waited for at exit

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