Memory management of golang function types

Function types in the Go language have value semantics, which means that when a function type variable is assigned or passed, its value will be copied rather than referenced, so changes to the variable will not affect the values ​​of other variables. For example, callback functions are passed as arguments to other functions to provide customized behavior. It should be noted that closure reference variables may cause memory leaks, and memory consumption should be considered when function type variables reference large objects.

Memory Management of Go Language Function Types

Function types are represented in the Go language as type values, just like any other type, such as an integer or a string. This means that function type variables can be copied between variables, passed to functions and stored in data structures.

Value semantics of function types

When a function type variable is assigned or passed, its value is copied rather than referenced. This means that changes made to this function type variable in different variables will not affect the value of the other variables.

func add(x, y int) int {
    return x + y
}

func main() {
    f := add  // 复制 f 对 add 的引用
    f(1, 2)    // 3
    g := f      // 再次复制 f 对 add 的引用
    g(3, 4)    // 7
    f(5, 6)    // 11
}

In the above example, f and g are independent copies pointing to the add function. Changes to f and g do not affect each other.

Practical case: callback function

The callback function is a function passed to another function as a parameter. For example, the sort.Sort function receives as argument a comparison function that determines the sort order of elements in a list.

package main

import (
    "fmt"
    "sort"
)

func main() {
    strs := []string{"Alice", "Bob", "Carol"}

    // 创建一个回调函数，按字符串长度比较
    compare := func(a, b string) int {
        return len(a) - len(b)
    }

    // 使用该回调函数对字符串进行排序
    sort.Slice(strs, compare)

    fmt.Println(strs) // ["Bob", "Alice", "Carol"]
}

In the above example, the compare function is passed to sort.Sort as the callback function. This callback function provides a way to customize the behavior of sort.Sort.

Traps

Although function types have value semantics, you need to pay attention to the following points:

• A closure reference variable will capture a reference to its outer environment, Cause memory leak.
• Function type variables can reference large objects, so it is important to consider memory consumption before passing or storing them.

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