Will the Go language main function wait? Explore and analyze

Will the main function of Go language wait? Exploration and Analysis

In the Go language, the main function is the entry point of the program and is responsible for starting the running of the program. Many beginners are confused as to whether the main function of the Go language will wait for other goroutines in the program to complete execution. This article will delve into this issue and explain it through specific code examples.

First of all, it should be clear that the main function in Go language does not wait for other parts of the program to complete execution like the main function in some other programming languages. The main function is only the starting point of the program. When the main function is executed, the program will terminate without waiting for the execution of other goroutines.

So, what if we need the main function to wait for certain goroutines to finish executing before ending? In Go language, we can use WaitGroup in sync package to achieve this purpose. WaitGroup is a synchronization primitive used to wait for a group of goroutines. It can help us control the execution order of goroutines and ensure that certain goroutines are executed before ending the program.

Below, we use a specific code example to demonstrate how the main function waits for the execution of goroutine:

package main

import (
    "fmt"
    "sync"
)

func worker(id int, wg *sync.WaitGroup) {
    defer wg.Done()
    fmt.Printf("Worker %d starting
", id)
    
    // 模拟一些执行时间
    for i := 0; i < 3; i++ {
        fmt.Printf("Worker %d working...
", id)
    }
    
    fmt.Printf("Worker %d done
", id)
}

func main() {
    var wg sync.WaitGroup
    
    for i := 1; i <= 3; i++ {
        wg.Add(1)
        go worker(i, &wg)
    }
    
    fmt.Println("Main function starting...")
    
    // 等待所有goroutine执行完毕
    wg.Wait()
    
    fmt.Println("Main function done.")
}

In this example, we define a worker function and simulate a time-consuming Task. In the main function, we start three worker goroutines and use WaitGroup to ensure that the main function ends after all worker goroutines have finished executing. By running this code, we can see that the main function will wait for all goroutines to finish executing before printing "Main function done.".

In summary, the main function of the Go language itself does not wait for other parts of the program to complete execution, but we can use WaitGroup in the sync package to realize the main function waiting for the execution of goroutine. Reasonably controlling the execution order of goroutines is an important means to ensure program correctness. I hope this article can inspire readers.

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