问题
Go Newbie question: I am trying to init the following struct, with a default value. I know that it works if "Uri" is a string and not pointer to a string (*string). But i need this pointer for comparing two instances of the struct, where Uri would be nil if not set, e.g. when i demarshal content from a json file. But how can I initialize such a struct properly as a "static default"?
type Config struct {
Uri *string
}
func init() {
var config = Config{ Uri: "my:default" }
}
The code above fails with
cannot use "string" (type string) as type *string in field value
回答1:
It's not possible to get the address (to point) of a constant value, which is why your initialization fails. If you define a variable and pass its address, your example will work.
type Config struct {
Uri *string
}
func init() {
v := "my:default"
var config = Config{ Uri: &v }
}
来源：https://stackoverflow.com/questions/42594789/initialize-string-pointer-in-struct