# package ioutil
`import "io/ioutil"`
Package ioutil implements some I/O utility functions.
## Index
* [Variables](#pkg-variables)
* [func NopCloser(r io.Reader) io.ReadCloser](#NopCloser)
* [func ReadAll(r io.Reader) ([]byte, error)](#ReadAll)
* [func ReadFile(filename string) ([]byte, error)](#ReadFile)
* [func WriteFile(filename string, data []byte, perm os.FileMode) error](#WriteFile)
* [func ReadDir(dirname string) ([]os.FileInfo, error)](#ReadDir)
* [func TempDir(dir, prefix string) (name string, err error)](#TempDir)
* [func TempFile(dir, prefix string) (f \*os.File, err error)](#TempFile)
## Variables
```
var Discard io.Writer = devNull(0)
```
Discard是一個io.Writer接口,對它的所有Write調用都會無實際操作的成功返回。
## func [NopCloser](https://github.com/golang/go/blob/master/src/io/ioutil/ioutil.go#L122 "View Source")
```
func NopCloser(r io.Reader) io.ReadCloser
```
NopCloser用一個無操作的Close方法包裝r返回一個ReadCloser接口。
## func [ReadAll](https://github.com/golang/go/blob/master/src/io/ioutil/ioutil.go#L41 "View Source")
```
func ReadAll(r io.Reader) ([]byte, error)
```
ReadAll從r讀取數據直到EOF或遇到error,返回讀取的數據和遇到的錯誤。成功的調用返回的err為nil而非EOF。因為本函數定義為讀取r直到EOF,它不會將讀取返回的EOF視為應報告的錯誤。
## func [ReadFile](https://github.com/golang/go/blob/master/src/io/ioutil/ioutil.go#L49 "View Source")
```
func ReadFile(filename string) ([]byte, error)
```
ReadFile?從filename指定的文件中讀取數據并返回文件的內容。成功的調用返回的err為nil而非EOF。因為本函數定義為讀取整個文件,它不會將讀取返回的EOF視為應報告的錯誤。
## func [WriteFile](https://github.com/golang/go/blob/master/src/io/ioutil/ioutil.go#L76 "View Source")
```
func WriteFile(filename string, data []byte, perm os.FileMode) error
```
函數向filename指定的文件中寫入數據。如果文件不存在將按給出的權限創建文件,否則在寫入數據之前清空文件。
## func [ReadDir](https://github.com/golang/go/blob/master/src/io/ioutil/ioutil.go#L100 "View Source")
```
func ReadDir(dirname string) ([]os.FileInfo, error)
```
返回dirname指定的目錄的目錄信息的有序列表。
## func [TempDir](https://github.com/golang/go/blob/master/src/io/ioutil/tempfile.go#L74 "View Source")
```
func TempDir(dir, prefix string) (name string, err error)
```
在dir目錄里創建一個新的、使用prfix作為前綴的臨時文件夾,并返回文件夾的路徑。如果dir是空字符串,TempDir使用默認用于臨時文件的目錄(參見os.TempDir函數)。?不同程序同時調用該函數會創建不同的臨時目錄,調用本函數的程序有責任在不需要臨時文件夾時摧毀它。
## func [TempFile](https://github.com/golang/go/blob/master/src/io/ioutil/tempfile.go#L47 "View Source")
```
func TempFile(dir, prefix string) (f *os.File, err error)
```
在dir目錄下創建一個新的、使用prefix為前綴的臨時文件,以讀寫模式打開該文件并返回os.File指針。如果dir是空字符串,TempFile使用默認用于臨時文件的目錄(參見os.TempDir函數)。不同程序同時調用該函數會創建不同的臨時文件,調用本函數的程序有責任在不需要臨時文件時摧毀它。
- 庫
- package achive
- package tar
- package zip
- package bufio
- package builtin
- package bytes
- package compress
- package bzip2
- package flate
- package gzip
- package lzw
- package zlib
- package container
- package heap
- package list
- package ring
- package crypto
- package aes
- package cipher
- package des
- package dsa
- package ecdsa
- package elliptic
- package hmac
- package md5
- package rand
- package rc4
- package rsa
- package sha1
- package sha256
- package sha512
- package subtle
- package tls
- package x509
- package pkix
- package database
- package sql
- package driver
- package encoding
- package ascii85
- package asn1
- package base32
- package base64
- package binary
- package csv
- package gob
- package hex
- package json
- package pem
- package xml
- package errors
- package expvar
- package flag
- package fmt
- package go
- package doc
- package format
- package parser
- package printer
- package hash
- package adler32
- package crc32
- package crc64
- package fnv
- package html
- package template
- package image
- package color
- package palette
- package draw
- package gif
- package jpeg
- package png
- package index
- package suffixarray
- package io
- package ioutil
- package log
- package syslog
- package math
- package big
- package cmplx
- package rand
- package mime
- package multipart
- package net
- package http
- package cgi
- package cookiejar
- package fcgi
- package httptest
- package httputil
- package pprof
- package mail
- package rpc
- package jsonrpc
- package smtp
- package textproto
- package url
- package os
- package exec
- package signal
- package user
- package path
- package filepath
- package reflect
- package regexp
- package runtime
- package cgo
- package debug
- package pprof
- package race
- package sort
- package strconv
- package strings
- package sync
- package atomic
- package text
- package scanner
- package tabwriter
- package template
- package time
- package unicode
- package utf16
- package utf8
- package unsafe