By convention, errors have type error, a simple built-in interface.

type error interface {
    Error() string
}

Usage

Basically as a part return from function

package main

import (
    "errors"
    "fmt"
)

func divide(a, b int) (int, error) {
    if b == 0 {
        return 0, errors.New("division by zero")
    }
    return a / b, nil
}

func main() {
    result, err := divide(10, 0)
    if err != nil {
        fmt.Println("Error:", err)
        return
    }
    fmt.Println("Result:", result)
}

Error vs. Panic

• Error: Recoverable
• Panic: Not Recoverable, exit and triggers defer , can be caught by recover

An example of panic

package main

import "fmt"

func main() {
    defer fmt.Println("First defer")
    defer fmt.Println("Second defer")

    defer func() {
        if r := recover(); r != nil {
            fmt.Println("Recovered:", r)
        }
    }()

    panic("Something bad happened")
    fmt.Println("This line will not be executed")
}