[英]Cast a struct pointer to interface pointer in Golang
I have a function 我有一个功能
func doStuff(inout *interface{}) {
...
}
the purpose of this function is to be able to treat a pointer of any type as input. 此函数的目的是能够将任何类型的指针视为输入。 But when I want to call it with a the pointer of a struct I have an error. 但是,当我想用结构的指针调用它时,我有一个错误。
type MyStruct struct {
f1 int
}
When calling doStuff
在调用doStuff
ms := MyStruct{1}
doStuff(&ms)
I have 我有
test.go:38: cannot use &ms (type *MyStruct) as type **interface {} in argument to doStuff
How can I cast &ms
to be compatible with *interface{}
? 如何使用&ms
来兼容*interface{}
?
There is no such thing as a "pointer to an interface" (technically, you can use one, but generally you don't need it). 没有“指向接口的指针”(技术上,你可以使用一个,但通常你不需要它)。
As seen in " what is the meaning of interface{} in golang? ", interface
is a container with two words of data: 如“ golang中接口{}的含义是什么? ”中所示, interface
是一个包含两个数据字的容器:
So remove the pointer, and doStuff
will work just fine: the interface data will be &ms
, your pointer: 所以删除指针, doStuff
将正常工作:接口数据将是&ms
,你的指针:
func doStuff(inout interface{}) {
...
}
See this example : 看这个例子 :
ms := MyStruct{1}
doStuff(&ms)
fmt.Printf("Hello, playground: %v\n", ms)
Output: 输出:
Hello, playground: {1}
As newacct mentions in the comments : 正如newacct 在评论中提到:
Passing the pointer to the interface directly works because if
MyStruct
conforms to a protocol, then*MyStruct
also conforms to the protocol (since a type's method set is included in its pointer type's method set). 将指针直接传递给接口是有效的,因为如果MyStruct
符合协议,那么*MyStruct
也符合协议(因为类型的方法集包含在其指针类型的方法集中)。In this case, the interface is the empty interface, so it accepts all types anyway, but still. 在这种情况下,接口是空接口,因此它仍然接受所有类型。
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