Critical section¶

Category: Synchronization · Status: stub · Lessons: chapter 02, Shared state

One line: A stretch of code that touches shared state and must not be run by two tasks at once.

Also called: critical region.

How it connects¶


Rust	As long as the `MutexGuard` ↗ lives: the mutex is unlocked when the guard is dropped
Go	Between `Mutex.Lock` ↗ and `Unlock`; a locked `Mutex` is not tied to the goroutine that locked it
C++	The scope of a `std::lock_guard` ↗, which owns the mutex for the duration of a scoped block
Java	A `synchronized` statement ↗: the monitor is unlocked whether the block completes normally or abruptly
Python	A `with lock:` block: `threading` primitives ↗ acquire on entry and release on exit
C#	The body of a `lock` statement ↗, released even if an exception is thrown
The operating system	Windows names an object after it: critical section objects ↗ work like a mutex for the threads of one process

In this library: Keeping every update
In a sibling library: Go: A mutex guards a counter ↗
In the books: Modern Multithreading, Richard H. Carver, Kuo-Chung Tai — ch. 2, 'The Critical Section Problem'
In the books: Learn Concurrent Programming with Go, James Cutajar — ch. 4, 'Synchronization with mutexes' → 'Protecting critical sections with mutexes'
In the books: Programming with POSIX Threads, David R. Butenhof — ch. 3, 'Synchronization' → 'Invariants, critical sections, and predicates'
In the books: Python Asyncio Jump-Start, Jason Brownlee — ch. 5, 'Queues and Synchronization Primitives' → 'How to Protect Critical Sections with a Mutex Lock'
In the books: The Art of Concurrency, Clay Breshears — ch. 3, 'Proving Correctness and Measuring Performance' → 'Example: The Critical Section Problem'
In the books: The Art of Multiprocessor Programming, Maurice Herlihy, Nir Shavit — ch. 2, 'Mutual Exclusion' → 'Critical Sections'
Reference: Wikipedia: Critical section ↗