Error handling and exception catching in go functions

In Go, error handling and exception capturing are implemented through the error interface and recover function. Errors are represented by the error return value, while exceptions are caught and handled through the panic and recover mechanisms. Practical cases demonstrate how to use error and defer statements to handle file operation errors.

Error handling and exception catching in Go functions

When writing code in Go, error handling and exception catching are important for writing Robust and stable applications are critical. This tutorial takes an in-depth look at error handling techniques in Go and illustrates them with a practical example.

Error handling

Error handling in Go relies on the error interface, which represents any error or exception condition. Functions can use a return value of type error to indicate error conditions. The receiving function can check this return value and take appropriate action, such as logging an error or terminating the program.

func example() error {
    // 在函数中处理错误
    return fmt.Errorf("some error occurred")
}

Exception catching

In Go, the concept of "exception" is slightly different from that in other programming languages. Go does not have a traditional exception mechanism, but relies on the recover function to capture and handle panics. Panic is an unhandled exception condition in a program that causes the program to terminate.

func example() {
    defer func() {
        if r := recover(); r != nil {
            // 在捕获 panic 后处理错误
            fmt.Println("Recovered from panic:", r)
        }
    }()

    // 抛出 panic 以模拟异常情况
    panic("some panic occurred")
}

Practical case

Suppose we have a function readFile, which reads and opens a file. If the file opening fails, the function returns an error.

import (
    "fmt"
    "os"
)

func readFile(filename string) error {
    f, err := os.Open(filename)
    if err != nil {
        return fmt.Errorf("error opening file: %w", err)
    }
    defer f.Close()
    return nil
}

We can use the defer statement to ensure that the file is closed after the function returns, even if an error occurs.

func main() {
    err := readFile("non-existing-file")
    if err != nil {
        // 处理错误
        fmt.Println("Error:", err)
    }
}

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