tcp客户端结束而未到达某些语句

Question

The code below is suppose to open a connection to a server, send a message and wait for a reply before ending but the problem is it isn't even reaching the end of the function. What could be wrong? Should I use wg sync.WaitGroup?

func client(servId uint16, servAddr string) {

    tcpAddr, err := net.ResolveTCPAddr("tcp", servAddr)
    check(err)

    conn, err := net.DialTCP("tcp", nil, tcpAddr)
    check(err)

    _, err = conn.Write(handshake(servId, 1500))
    check(err)

    init := make([]byte, 8)
    _, err = io.ReadFull(conn, init)
    check(err)

    fmt.Println("is reached") // doesn't get printed WHY?
    fmt.Println(init)
}

How the function above is called from main

// vars
var c, startId, servId uint16

// for each servers
for s := 0; s < len(config.Servers); s++ {

    // for each connection
    for c = 0; c < config.Total_clients; c++ {

        startId = config.Server_id * config.Total_clients
        servId = startId + c

        servAddr := fmt.Sprintf("%s:%d", config.Servers[s].Host, config.Servers[s].Port)

        // create the clients in new go routines
        go client(servId, servAddr)
    }

}

Answer 1

Your program will exit before it finishes executing, you need to use sync.WaitGroup or channels to wait for all the output before exiting.

func client(wg *sync.WaitGroup, servId uint16, servAddr string) {
    defer wg.Done()
.....
}

func main() {
    var (
        c, startId, servId uint16
        wg                 sync.WaitGroup
    )
    for _, srv := range config.Servers {
        for c = 0; c < config.Total_clients; c++ {
        ......
            wg.Add(1)
            go client(&wg, servId, servAddr)
        }
    }
    wg.Wait()
}