用goroutines调用非goroutine函数

Question

I have part of a script with the following format:

func main() {
  for i=0;i<1000000;i++ {
    go test()
  }
}
func test() {
    a := test2()
}
func test2()(var int) {
    //a bunch of operations
    return var
}

I run a lot of iterations and it always work. I'm wondering is there any chance that two or more goroutines calling function "test2()" at the same time and cause a crash? Is the following format anyway better then the previous one?

func main() {
    for i=0;i<1000000;i++ {
        go test()
    }
}
func test() {
    test2 := func()(var int){
        //a bunch of operations
        return var
    }
    a := test2()
}

Thank you very much!

Answer 1

No, your function will not crash, unless there is something wrong in your code (ie division by zero) or you explicitly call panic() . If it doesn't access any fields (or methods whose documentation doesn't specify they may be called concurrently), then your function is thread-safe .

EDIT: The first code is better. Although both should have very similar performance, since they are running the same code, the first is easier to read. There may be a small performance penalty in your second code block, since you are defining a function multiple times, but that is probably optimized away by the compiler.