How to use a mutex to define critical sections of code and fix race conditions?
A mutex is used to create a critical section around code that ensures only one goroutine at a time can execute that code section.
A critical section defined by the calls to Lock() and Unlock() protects the actions against the counter variable and reading the text of name variable.
Example
package main
import (
"fmt"
"sync"
)
var (
counter int32 // counter is a variable incremented by all goroutines.
wg sync.WaitGroup // wg is used to wait for the program to finish.
mutex sync.Mutex // mutex is used to define a critical section of code.
)
func main() {
wg.Add(3) // Add a count of two, one for each goroutine.
go increment("Python")
go increment("Go Programming Language")
go increment("Java")
wg.Wait() // Wait for the goroutines to finish.
fmt.Println("Counter:", counter)
}
func increment(lang string) {
defer wg.Done() // Schedule the call to Done to tell main we are done.
for i := 0; i < 3; i++ {
mutex.Lock()
{
fmt.Println(lang)
counter++
}
mutex.Unlock()
}
}
Output
C:\Golang\goroutines>go run -race main.go
PHP stands for Hypertext Preprocessor.
PHP stands for Hypertext Preprocessor.
The Go Programming Language, also commonly referred to as Golang
The Go Programming Language, also commonly referred to as Golang
Counter: 4
C:\Golang\goroutines>