Concurrency issues in the life cycle of Golang functions

Concurrent function life cycle issues: variable escape: The life cycle of a variable exceeds its definition scope, resulting in race conditions for shared variables between different goroutines. Local variable competition: When different goroutines execute the same function concurrently, their local variables are created in different stack spaces, resulting in unexpected values. Workaround: Use a mutex to serialize access to shared variables. Safely modify shared variables using atomic operations. Use unbuffered channels to avoid write race conditions. Create a write-only copy of the variable and pass it to the goroutine.

Concurrency issues in the function life cycle in Go

In concurrent programming, race conditions in the function life cycle are a common trap. This problem occurs when multiple goroutines access variables in the function scope at the same time.

Variable Escape

In Go, variable escape means that the life cycle of a variable exceeds its definition scope. This usually happens when a variable is passed to a closure or as a function return value.

Practical case:

func main() {
    i := 0
    go func() {
        i++ // i 变量逃逸到了闭包作用域
    }()
    fmt.Println(i) // 可能打印 0 或 1
}

In this example, the address of the i variable is passed to the goroutine, causing the variable to escape. This creates a race condition between different goroutines, since they can all modify variable i.

Local variable competition

In Go, each function has its own private stack space for storing its local variables. When multiple goroutines execute the same function at the same time, they will create local variables in different stack spaces.

Practical case:

func inc(i int) int {
    i++ // 对局部变量 i 进行递增
    return i
}

func main() {
    var wg sync.WaitGroup
    for i := 0; i < 100; i++ {
        wg.Add(1)
        go func() {
            fmt.Println(inc(i)) // 局部变量 i 的竞争
            wg.Done()
        }()
    }
    wg.Wait()
}

In this example, the goroutine calls the inc function concurrently and tries to modify the local variable iIncrement. Since each goroutine uses different stack space, their i variables are actually different. This can cause unexpected values ​​in the output.

Solving concurrency problems

In order to solve these concurrency problems, you can use the following techniques:

• Mutex locks: Use mutex locks to Serialize access to shared variables.
• Atomic operations: Use atomic operations to safely modify shared variables.
• Unbuffered Channels: Use unbuffered channels to avoid write race conditions.
• Write-only copy: Create a write-only copy of the variable and pass it to the goroutine.

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