What are the core concepts covered in sync.WaitGroup, sync.Mutex & Race Detector (-race)?

Waiting for N concurrent workers with sync.WaitGroup (Add, Done, Wait); Protecting critical shared variables with sync.Mutex and sync.RWMutex; Running the Go Race Detector (go test -race) to catch data races

Advanced 20 min readModule: Module 10: Sync Primitives (Mutex, WaitGroup, Once)

sync.WaitGroup, sync.Mutex & Race Detector (-race)

Synchronize goroutine completion with WaitGroup, protect shared memory with Mutex, and detect race conditions.

What You Will Learn in This Lesson

Waiting for N concurrent workers with sync.WaitGroup (Add, Done, Wait)
Protecting critical shared variables with sync.Mutex and sync.RWMutex
Running the Go Race Detector (go test -race) to catch data races

Introduction & Core Concept

When channels are not appropriate, the standard library 'sync' package provides classical low-level synchronization primitives like Mutexes and WaitGroups.

WHY DOES THIS MATTER IN THE REAL WORLD?

Running 'go run -race' detects subtle multithreaded memory corruption before code reaches production.

sync.WaitGroup Coordination

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package main
import (
    "fmt"
    "sync"
)
 
func main() {
    var wg sync.WaitGroup
    for i := 1; i <= 3; i++ {
        wg.Add(1)
        go func(id int) {
            defer wg.Done()
            fmt.Printf("Worker #%d done\n", id)
        }(i)
    }
    wg.Wait() // Block until all 3 workers call Done()
    fmt.Println("All workers finished.")
}

Line-by-Line Technical Breakdown

1Always pass WaitGroup pointers (&wg), never pass WaitGroups by value.

Try It Yourself (Interactive Editor)

Modify the code in real-time and click Run to test live browser output and console logs.

Intelligent Code Runner & Live Sandbox[GO]

GO SOURCE EDITOR

Interactive Live Code

>go run -race main.go

>Worker #val done\n, id

>All workers finished.

Industry Best Practices & Professional Standards

Always run tests with the -race flag enabled in CI pipelines.

Lesson Summary & Core Takeaways

Sync primitives coordinate parallel tasks and protect shared state.