errors - The Go Programming Language

Golang

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Package errors

import "errors"

Overview

Index

Examples

Overview ?

Package errors implements functions to manipulate errors.

? Example

Code:

package errors_test

import (
    "fmt"
    "time"
)

// MyError is an error implementation that includes a time and message.
type MyError struct {
    When time.Time
    What string
}

func (e MyError) Error() string {
    return fmt.Sprintf("%v: %v", e.When, e.What)
}

func oops() error {
    return MyError{
        time.Date(1989, 3, 15, 22, 30, 0, 0, time.UTC),
        "the file system has gone away",
    }
}

func Example() {
    if err := oops(); err != nil {
        fmt.Println(err)
    }
    // Output: 1989-03-15 22:30:00 +0000 UTC: the file system has gone away
}

Index

func New(text string) error

Examples

Package

New

New (Errorf)

Package files

errors.go

func New

func New(text string) error

New returns an error that formats as the given text.

? Example

Code:

err := errors.New("emit macho dwarf: elf header corrupted")
if err != nil {
    fmt.Print(err)
}

Output:

emit macho dwarf: elf header corrupted

? Example (Errorf)

The fmt package's Errorf function lets us use the package's formatting features to create descriptive error messages.

Code:

const name, id = "bimmler", 17
err := fmt.Errorf("user %q (id %d) not found", name, id)
if err != nil {
    fmt.Print(err)
}

Output:

user "bimmler" (id 17) not found

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