go - Golang 中的调用函数

Question

我有这样一个函数:

var flagvar int
func init() {
    flag.IntVar(&flagvar, "flagname", 1234, "help message for flagname")
}

我想在func main()中调用它:

func main(){
  init()
}

但它不起作用，并告诉我 init() 未定义。有什么问题？

Answer 1

init函数是Golang中的一个特殊函数。它在第一次加载文件时执行，因此您永远不必直接调用它。

来自官方文档:

Finally, each source file can define its own niladic init function to set up whatever state is required. (Actually each file can have multiple init functions.) And finally means finally: init is called after all the variable declarations in the package have evaluated their initializers, and those are evaluated only after all the imported packages have been initialized.