golang function calling process

Golang function calling process

Go is a relatively young language, but it is widely used in engineering practice. Go implements efficient and easy-to-maintain concurrent programming through garbage collection mechanisms and coroutines. As an object-oriented language, functions are one of its most basic components. Therefore, this article will explore the Golang function calling process in detail.

All programs in Go have an entry point, which is the main() function. When the program starts, the operating system will start a process and hand over program control to the main() function. In the main() function, the program will call other functions to complete its tasks. The process of function calling is as follows:

1. Execute function declaration

When defining a function in code, you need to provide basic information such as function name, parameter list, and return value type. This information makes up the function's declaration.

For example:

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

In this code, the declaration of the add() function contains the function name, the type int of the two parameters x and y, and the return type int of the function.

The function declaration just tells the compiler that there is a function called add(), and lets the compiler know that it requires two parameters of type int and returns a value of type int.

2. Execute function call

In the main() function, if you want to call the add() function, you only need to provide the function name and parameters:

result := add(1, 2)

This line of code will pass 1 and 2 as parameters to the add() function and store the return value in the result variable.

3. Execute function body

When the add() function is called, the program will jump to the location where the function is defined, execute the logic in the function body, and finally return the result.

Here, the add() function will add the two parameters received and return their sum, which is 3.

4. Return results

When the add() function completes execution, it will return the result to the caller. In this example, the return value of the function call statement add(1, 2) is 3, so the program will assign 3 to the variable result.

The entire process of function calling is as follows:

It should be noted that function calls in Go are passed by value, not by reference. This means that if a function parameter changes, its value outside the function will not be affected. If you need to modify the value of a parameter inside a function and make the change persist outside the function, you need to pass the pointer of the parameter.

In summary, functions are one of the most commonly used components in Golang programming. When calling a function, the program will pass control to the called function at the time of the call, execute the function body and return the results to the caller. This is a simple but powerful way to split the program into smaller, more maintainable part.

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