Concurrency safety of golang functions

The concurrency safety of Go functions means that the function can still operate correctly when called concurrently, avoiding damage caused by multiple goroutines accessing data at the same time. Concurrency-safe functions can use methods such as locks, channels, or atomic variables. Locks allow goroutines to have exclusive access to critical sections, channels provide a secure communication mechanism, and atomic variables provide concurrent secure access to specific variables. In actual cases, channels are used to implement concurrency safety functions to ensure that multiple goroutines access shared resources in the correct order.

Concurrency safety of Go language functions

In Go, concurrency safety refers to ensuring that functions can still operate correctly when called concurrently. In other words, the function must ensure that its internal state is not corrupted by simultaneous access from multiple goroutines.

Example of a concurrency-unsafe function

The following is an example of a concurrency-unsafe function:

var counter int

func IncrementCounter() {
    counter++
}

Even if counter is declared as atomic Integer, this function is still unsafe because there is no synchronization mechanism to protect access to counter. This means that multiple goroutines may try to increment counter at the same time, causing data races.

Implementing concurrency-safe functions

To create concurrency-safe functions, you can use several different methods.

1. Using locks

Lock is a synchronization mechanism that allows goroutine to acquire a lock before entering the critical section (the code segment that accesses shared resources). Once a goroutine acquires the lock, it has exclusive access to the critical section. For example:

var mu sync.Mutex

func IncrementCounter() {
    mu.Lock()
    defer mu.Unlock()
    counter++
}

2. Using channels

Channels are a mechanism for secure communication between goroutines. Channels can be used to pass messages or synchronize the execution of goroutines. For example:

var incrementChan = make(chan struct{})

func IncrementCounter() {
    incrementChan <- struct{}{}
    <-incrementChan
    counter++
}

3. Using atomic variables

Atomic variables are a special type of variables that provide concurrent and safe access to variables. The Go language provides several built-in atomic variables, such as:

import "sync/atomic"

var counter int64

func IncrementCounter() {
    atomic.AddInt64(&counter, 1)
}

Practical case

The following is a practical case using channels to implement concurrent safety functions:

package main

import (
    "fmt"
    "sync"
)

var wg sync.WaitGroup

func main() {
    ch := make(chan struct{})

    for i := 0; i < 100; i++ {
        wg.Add(1)
        go func() {
            defer wg.Done()
            <-ch
            fmt.Println("Goroutine:", i)
        }()
    }

    close(ch)
    wg.Wait()
}

This program 100 goroutines are created, each goroutine receives a message from channel ch. When a channel is closed, all goroutines are woken up and their IDs are printed in the correct order.

By using channels, we can ensure that goroutines will not access shared resources (i.e. channels) at the same time, thereby achieving concurrency safety.

The above is the detailed content of Concurrency safety of golang functions. For more information, please follow other related articles on the PHP Chinese website!