https://wiki.quizz.vn/ 2026-04-15T18:11:51+00:00 https://wiki.quizz.vn/ https://wiki.quizz.vn/lib/exe/fetch.php?media=wiki:dokuwiki.svg text/html 2025-12-29T23:19:38+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.quizz.vn/doku.php?id=go:concurrency:atomic&rev=1767050378&do=diff sync/atomic What is it? `sync/atomic` provides low-level atomic memory primitives for safe, lock-free access to shared integer and pointer values. What is it used for? * Perform simple concurrent operations without using `Mutex`. * Common ops: atomic add, load/store, compare-and-swap (CAS). text/html 2026-01-05T22:41:56+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.quizz.vn/doku.php?id=go:concurrency:cancel&rev=1767652916&do=diff WithCancel What is it? `context.WithCancel(parent)` creates a child context that can be canceled manually by calling the returned `cancel()` function. Signature: `ctx, cancel := context.WithCancel(parent)` What is it used for? * Stop background goroutines when you’re done. text/html 2025-12-28T22:45:07+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.quizz.vn/doku.php?id=go:concurrency:channel&rev=1766961907&do=diff Channel What is it? A channel is a typed conduit for sending and receiving values between goroutines. It helps coordinate and synchronize concurrent work. What is it used for? * Pass data safely between goroutines. * Avoid complicated shared-memory locking. text/html 2025-12-29T23:17:46+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.quizz.vn/doku.php?id=go:concurrency:cond&rev=1767050266&do=diff sync.Cond What is it? `sync.Cond` is a condition variable. It lets goroutines wait until a certain condition becomes true, and be signaled when it changes. What is it used for? * Implement producer-consumer patterns. * Build your own blocking queues or resource pools. text/html 2026-01-05T22:38:04+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.quizz.vn/doku.php?id=go:concurrency:context&rev=1767652684&do=diff context.Context What is it? `context.Context` is a standard way to carry: * deadlines, * cancellation signals, * and request-scoped values across API boundaries and between goroutines. What is it used for? * Cancel work when a request is no longer needed (client disconnected, timeout, shutdown). text/html 2026-01-05T22:46:12+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.quizz.vn/doku.php?id=go:concurrency:deadline&rev=1767653172&do=diff WithDeadline What is it? `context.WithDeadline(parent, t)` creates a child context that is canceled at the specific time `t` (a `time.Time`). Signature: `ctx, cancel := context.WithDeadline(parent, t)` What is it used for? * Enforce a fixed cutoff time (e.g., must finish before 10:00:05). text/html 2025-12-28T22:44:39+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.quizz.vn/doku.php?id=go:concurrency:goroutine&rev=1766961879&do=diff Goroutine What is it? A goroutine is a lightweight thread managed by the Go runtime. You start it with the `go` keyword. What is it used for? * Run tasks concurrently: I/O, API calls, background jobs. * Improve server throughput by doing work in parallel. text/html 2025-12-29T23:02:30+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.quizz.vn/doku.php?id=go:concurrency:mutex&rev=1767049350&do=diff sync.Mutex What is it? `sync.Mutex` is a mutual exclusion lock used to protect shared data from concurrent access. What is it used for? * Prevent data races when multiple goroutines read/write the same variable/structure. * Protect critical sections (a block of code that must not run concurrently). text/html 2025-12-29T23:16:57+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.quizz.vn/doku.php?id=go:concurrency:once&rev=1767050217&do=diff sync.Once What is it? `sync.Once` ensures that a function is executed only once, even when called by multiple goroutines concurrently. What is it used for? * One-time initialization (lazy init), e.g., create a singleton, load config once. * Safe text/html 2025-12-29T23:13:23+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.quizz.vn/doku.php?id=go:concurrency:rwmutex&rev=1767050003&do=diff sync.RWMutex What is it? `sync.RWMutex` is a read/write mutual exclusion lock. It allows multiple readers at the same time, but only one writer (and writers exclude readers). What is it used for? * Protect shared data that is read very often but written less frequently. text/html 2026-01-30T23:14:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.quizz.vn/doku.php?id=go:concurrency:select&rev=1769814876&do=diff Go select with Non-blocking Send and Receive Overview In Go, the select statement allows a goroutine to wait on multiple channel operations. When combined with a default case, select can be used to perform non-blocking send and receive operations on channels. text/html 2026-01-05T22:33:34+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.quizz.vn/doku.php?id=go:concurrency:sync&rev=1767652414&do=diff sync package What is it? `sync` is a Go standard library package that provides basic synchronization primitives for coordinating goroutines and protecting shared data. What is it used for? * Protect shared resources from concurrent access (locks). text/html 2026-01-05T22:43:32+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.quizz.vn/doku.php?id=go:concurrency:timeout&rev=1767653012&do=diff WithTimeout What is it? `context.WithTimeout(parent, d)` creates a child context that is automatically canceled after duration `d`. Signature: `ctx, cancel := context.WithTimeout(parent, d)` What is it used for? * Time-limit outgoing HTTP requests. text/html 2026-01-05T22:46:55+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.quizz.vn/doku.php?id=go:concurrency:values&rev=1767653215&do=diff WithValue What is it? `context.WithValue(parent, key, val)` returns a child context that carries a key/value pair. Signature: `ctx := context.WithValue(parent, key, val)` What is it used for? * Carry request-scoped metadata like request-id, trace-id, user-id. text/html 2025-12-29T23:15:21+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.quizz.vn/doku.php?id=go:concurrency:waitgroup&rev=1767050121&do=diff sync.WaitGroup What is it? `sync.WaitGroup` is a counter-based synchronization primitive used to wait for a set of goroutines to finish. What is it used for? * Start N goroutines and wait until all of them are done. * Coordinate parallel tasks (fan-out) and join results (fan-in).