How to use Go language to achieve global visibility

Go language is a powerful programming language that excels in both performance and code security. It supports concurrent programming and has good concurrent processing capabilities. However, sometimes we need to make certain variables or functions visible throughout the program, in which case we need to achieve global visibility. This article will introduce how to use Go language to achieve global visibility.

1. Global variables

In Go language, we can use global variables to achieve global visibility. Global variables are defined outside the function, and their scope is visible throughout the package, so they can be called by any function.

The syntax for defining a global variable is as follows:

var 变量名 数据类型

For example:

var globalVar int

Global variables must be defined outside the function and assigned inside the main function. Global variables can be used directly within other functions.

2. Global functions

Similar to global variables, we can also use global functions to achieve global visibility. Global functions are functions defined in the Go language that have nothing to do with structures.

The syntax for defining a global function is as follows:

func 函数名(参数列表)(返回值列表){
    //函数体
}

For example:

func GlobalFunc() string{
    return "Hello World!"
}

Similarly, global functions must also be defined outside the function and called inside the main function.

3. Exported functions

The visibility in Go language is related to the case of the first letter. Only variables or functions starting with a capital letter can be called externally. Such variables or functions are called exported functions or exported variables.

The syntax for defining an exported function or exported variable is as follows:

var 变量名 数据类型 //定义一个导出变量
func 函数名(参数列表)(返回值列表){ //定义一个导出函数
    //函数体
}

For example:

var GlobalVar int //定义一个导出变量
func GlobalFunc() string{ //定义一个导出函数
    return "Hello World!"
}

The name of the exported variable or function must start with a capital letter before it can be included in other packages code accessed.

4. Constant definition

Constant is also an immutable global variable. When a constant is not assigned a value, the default value is 0, and it can be globally visible through constant definition.

The syntax for defining a constant is as follows:

const 常量名 数据类型 = 值

For example:

const GlobalConst int = 1

After a constant is defined, it can be called throughout the program.

5. Structure Definition

The structure is a complex global variable type that can be used throughout the program.

The syntax for defining a structure is as follows:

type 结构体名 struct{
    字段名 数据类型
}

For example:

type Student struct{
    Name string
    Age  int
}

After defining the structure, we can use the structure to define variables, for example:

var student Student
student.Name = "Tom"
student.Age = 20

You can also define the structure as a global variable:

var globalStudent Student

In this way, we can use Student type variables throughout the program.

6. Summary

Generally speaking, through the above method, we can achieve global visibility in the Go language. Among them, global variables, global functions, exported functions, constant definitions and structure definitions are all effective methods to achieve global visibility. You only need to choose the appropriate method according to your needs, and you can easily implement globally visible functions.

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