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 (i.e. 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.