How to Fix \'fatal error: all goroutines are asleep - deadlock\' in Go?

Go: Understanding and Resolving "fatal error: all goroutines are asleep - deadlock"

When executing a Go program, encountering the error message "fatal error: all goroutines are asleep - deadlock" indicates that all the program's goroutines (lightweight threads) are blocked indefinitely, resulting in a deadlock.

In the provided code, this issue arises due to the unbuffered nature of the "file1chan" channel. When a value is sent to an unbuffered channel, it blocks if no other goroutine is ready to receive it. In this case, the main goroutine sends values to "file1chan" without any concurrent goroutines receiving from it, leading to a deadlock.

Solution 1: Introduce a Concurrency Pattern

To resolve the deadlock, introduce a separate, concurrent goroutine that receives values from "file1chan" and avoids blocking the main goroutine. The modified code with a goroutine approach below:

func main() {
    f, _ := os.Open("D:\input1.txt")
    scanner := bufio.NewScanner(f)
    file1chan := make(chan string)
    go func() { 
        for scanner.Scan() {
            line := scanner.Text()
            parts := strings.Fields(line)
            for i := range parts {
                file1chan <- parts[i]
            }
        }
        close(file1chan)
    }()
    print(file1chan) 
}

Solution 2: Use a Buffered Channel

Alternatively, you can use a buffered channel to handle a fixed number of values without causing a deadlock. A buffered channel with a capacity of one is sufficient for this task:

func main() {
    f, _ := os.Open("D:\input1.txt")
    scanner := bufio.NewScanner(f)
    file1chan := make(chan string, 1)
    for scanner.Scan() {
        line := scanner.Text()
        parts := strings.Fields(line)
        for i := range parts {
            file1chan <- parts[i]
        }
    }
    close(file1chan)
    print(file1chan)
}

With a buffered channel, the sender can continue executing even if the receiver is not yet ready, thus avoiding the deadlock.

The above is the detailed content of How to Fix \'fatal error: all goroutines are asleep - deadlock\' in Go?. For more information, please follow other related articles on the PHP Chinese website!