Revealing the magic of Golang function addresses

The function address is the location of the function in memory and can be obtained using the & operator in Go. Function addresses can be passed as arguments (like callbacks), or used with reflection to inspect and manipulate function details (like function addresses).

Uncovering the magic of Golang function addresses

In Golang, functions are a first-class citizen, which means they can be like Assigned, passed and compared like any other value. This feature provides powerful tools for implementing various programming patterns, such as callbacks, closures, and reflection.

The function address refers to the location of the function in memory. In Golang, you can get the address of a function by using the & operator. For example:

func add(a, b int) int {
  return a + b
}

// 获取 add 函数的地址
funcAddr := &add

Practical case: Passing functions as parameters

We can pass the function address to other functions as parameters. This is a common pattern in Golang and is called callbacks. For example, we can pass the add function to the sort.Sort function to sort the slices:

package main

import (
  "fmt"
  "sort"
)

func main() {
  // 定义一个 int 切片
  nums := []int{5, 2, 9, 1, 3}

  // 按照升序对切片进行排序
  sort.Slice(nums, func(i, j int) bool {
    return nums[i] < nums[j]
  })

  fmt.Println(nums) // [1 2 3 5 9]
}

Practical example: using reflection

Reflection is an advanced feature in Golang that allows programs to inspect and manipulate types and values ​​at runtime. We can use reflection to get the details of a function, including its address. For example:

package main

import (
  "fmt"
  "reflect"
)

func main() {
  // 获取 add 函数的类型信息
  funcType := reflect.TypeOf(add)

  // 获取函数的地址
  funcValue := reflect.ValueOf(add)
  funcPtr := funcValue.Pointer()

  fmt.Println(funcPtr) // 类似于 &add
}

By understanding function addresses, you will be able to take advantage of Golang functions as first-class citizens and thus write more flexible and powerful programs.

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