libevent参考手册中文版_libevent-2.1.5.pdf_libevent参考手册,libevent手册

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libevent

参考手册

(

中文版

)

2016.01.31

说明，下面的文字我主要参考网文《libevent 参考手册(中文版)》和结合源码 libevent-2.1.5-beta 进行整理而得

libevent 参考手册(中文版)...................................................................................................................................................... 1

1 前言(R ef0_meta . html ) ........................................................................................................................................................ 5

1.1 其设计目标 ..................................................................................................................................................................... 6

1.2 libevent 由下列组件构成 ............................................................................................................................................... 6

1.3 库 ................................................................................................................................................................................... 6

1.4 头文件 ............................................................................................................................................................................ 6

1.5 关于版本状态的提示 ....................................................................................................................................................... 7

2 设置 libevent (Ref1_libsetup.html ) ...................................................................................................................................... 7

2.1 Libevent 中的日志消息..................................................................................................................................................... 7

2.1.1 接口 ............................................................................................................................................................................. 7

2.1.2 示例: ............................................................................................................................................................................. 8

2.1.3 注意: ............................................................................................................................................................................. 9

2.2 处理致命错误 ................................................................................................................................................................. 9

2.2.1 接口 ............................................................................................................................................................................. 9

2.3 内存管理 ........................................................................................................................................................................ 9

2.3.1 接口 ............................................................................................................................................................................. 9

2.3.2 示例 ........................................................................................................................................................................... 10

2.3.3 注意 ........................................................................................................................................................................... 11

2.4 锁和线程 ...................................................................................................................................................................... 11

2.4.1 使用线程库类型 .......................................................................................................................................................... 11

2.4.2 使用自定义线程库 ...................................................................................................................................................... 12

2.4.3 调试锁的使用 ............................................................................................................................................................. 13

2.5 调试事件的使用 ............................................................................................................................................................ 14

2.5.1 启用调试模式接口 ...................................................................................................................................................... 14

2.5.2 示例 ........................................................................................................................................................................... 14

2.5.3 注意 ........................................................................................................................................................................... 15

2.6 检测 libevent 的版本 .................................................................................................................................................... 15

2.6.1 接口 ........................................................................................................................................................................... 15

2.6.2 示例：编译时检测 ...................................................................................................................................................... 16

3.6.3 示例：运行时检测 ...................................................................................................................................................... 16

2.6.4 注意 ........................................................................................................................................................................... 17

2.7 释放全局 Libevent 结构.................................................................................................................................................. 17

2.7.1 接口 ........................................................................................................................................................................... 17

2.7.2 注意 ........................................................................................................................................................................... 17

3 创建 event_base (Ref2_eventbase.html) ............................................................................................................................. 17

3.1 建立默认的 event_base ................................................................................................................................................. 18

3.1.1 接口 ........................................................................................................................................................................... 18

3.2 创建复杂的 event_base ................................................................................................................................................. 18

3.2.1 接口 ........................................................................................................................................................................... 18

3.2.2 接口 ........................................................................................................................................................................... 18

3.2.3 接口 ........................................................................................................................................................................... 19

3.2.4 接口 ........................................................................................................................................................................... 19

3.2.5 示例：首选边缘触发后端 ........................................................................................................................................... 20

3.2.6 示例：避免优先倒置 .................................................................................................................................................. 20

3.3 检查 event_base 的后端方法 ........................................................................................................................................ 21

3.3.1 接口 ........................................................................................................................................................................... 21

3.3.2 接口 ........................................................................................................................................................................... 21

3.4 释放 event_base ........................................................................................................................................................... 22

3.4.1 接口 ........................................................................................................................................................................... 22

3.4.2 注意 ........................................................................................................................................................................... 22

3.5 设置 event_base 的优先级............................................................................................................................................ 22

3.5.1 接口 ........................................................................................................................................................................... 22

3.5.2 接口 ........................................................................................................................................................................... 22

3.5.3 示例 ........................................................................................................................................................................... 22

3.6 在 fork()之后重新初始化 event_base ............................................................................................................................. 23

3.6.1 接口 ........................................................................................................................................................................... 23

3.6.2 示例 ........................................................................................................................................................................... 23

3.7 废弃的 event_base 函数 ............................................................................................................................................... 23

4 与事件循环一起工作(Ref3_eventloop.html)........................................................................................................................ 24

4.1 运行循环 ...................................................................................................................................................................... 24

4.1.1 接口 ........................................................................................................................................................................... 24

4.1.2 接口 ........................................................................................................................................................................... 25

4.2 停止循环 ...................................................................................................................................................................... 25

4.2.1 接口 ........................................................................................................................................................................... 25

4.2.2 示例：立即关闭 ......................................................................................................................................................... 25

4.2.3 示例：执行事件循环 10 秒，然后退出 ........................................................................................................................ 26

4.2.4 检测退出方式 ............................................................................................................................................................. 26

4.2.5 注意 ........................................................................................................................................................................... 26

4.3 重新检查 events ............................................................................................................................................................ 26

4.4 检查内部时间缓存 ........................................................................................................................................................ 27

4.4.1 接口 ........................................................................................................................................................................... 27

4.4.2 注意 ........................................................................................................................................................................... 27

4.5 转储 event_base 的状态 ............................................................................................................................................... 27

4.5.1 接口 ........................................................................................................................................................................... 27

4.6 在 event_base 中的每个事件上运行一个函数 ................................................................................................................. 27

4.7 废弃的事件循环函数 ..................................................................................................................................................... 28

5 与 event 一起工作(Ref4_event.html) .................................................................................................................................. 28

5.1 构造 event 对象.............................................................................................................................................................. 29

5.1.1 接口 ........................................................................................................................................................................... 29

5.1.2 示例 ........................................................................................................................................................................... 29

5.1.3 注意 ........................................................................................................................................................................... 30

5.1.4 Event 标志 ................................................................................................................................................................... 30

5.1.5 关于事件持久性 ......................................................................................................................................................... 30

5.1.6 只有超时的事件 ......................................................................................................................................................... 31

5.1.7 构造信号事件 libevent ................................................................................................................................................ 32

5.1.8 设置不使用堆分配的 event ......................................................................................................................................... 33

5.2 让事件未决和非未决 ..................................................................................................................................................... 35

5.2.1 接口 ........................................................................................................................................................................... 35

5.2.2 接口 ........................................................................................................................................................................... 35

5.2.3 接口 ........................................................................................................................................................................... 35

5.3 带优先级的事件 ............................................................................................................................................................ 36

5.3.1 接口 ........................................................................................................................................................................... 36

5.3.2 示例 ........................................................................................................................................................................... 36

5.4 检查事件状态 ............................................................................................................................................................... 36

5.4.1 接口............................................................................................................................................................................ 36

5.4.2 示例 ........................................................................................................................................................................... 37

5.5 查找当前正在运行的 even ............................................................................................................................................. 38

5.5.1 接口............................................................................................................................................................................ 38

5.5.2 注意 ........................................................................................................................................................................... 38

5.6 配置一次触发事件 ........................................................................................................................................................ 38

5.6.1 接口 ........................................................................................................................................................................... 38

5.7 手动激活事件 ............................................................................................................................................................... 38

5.7.1 接口 ........................................................................................................................................................................... 38

5.7.2 错误示例:使用 event_active()产生一个无休止的循环 .................................................................................................... 39

5.7.3 示例: 使用定时器来解决上面的问题的可选方案 ......................................................................................................... 39

5.7.4 示例: 使用 event_config_set_max_dispatch_interval()来解决上面的问题的可选方案 ...................................................... 40

5.8 优化公用超时 ............................................................................................................................................................... 40

5.8.1 接口 ........................................................................................................................................................................... 40

5.8.2 示例 ........................................................................................................................................................................... 41

5.9 从已清除的内存识别事件 .............................................................................................................................................. 41

5.9.1 接口 ........................................................................................................................................................................... 41

5.9.2 警告 ........................................................................................................................................................................... 41

5.9.3 示例 ........................................................................................................................................................................... 42

5.10 废弃的事件操作函数 ................................................................................................................................................... 42

5.10.1 接口 .......................................................................................................................................................................... 42

6 辅助类型和函数(Ref5_evutil.mht) ...................................................................................................................................... 43

6.1 基本类型 ....................................................................................................................................................................... 43

6.1.1 evutil_socket_t ............................................................................................................................................................. 43

6.1.2 标准整数类型 ............................................................................................................................................................. 43

6.1.3 各种兼容性类型 ......................................................................................................................................................... 44

6.2 定时器可移植函数 ........................................................................................................................................................ 44

6.2.1 接口 ........................................................................................................................................................................... 44

6.2.2 接口 ........................................................................................................................................................................... 45

6.2.3 接口 ........................................................................................................................................................................... 45

6.2.4 接口 ........................................................................................................................................................................... 45

6.2.5 示例 ........................................................................................................................................................................... 45

6.3 套接字 API 兼容性 ....................................................................................................................................................... 46

6.3.1 接口 ........................................................................................................................................................................... 46

6.3.2 接口 ........................................................................................................................................................................... 46

6.3.3 接口 ........................................................................................................................................................................... 46

6.3.4 接口 ........................................................................................................................................................................... 47

6.3.5 接口 ........................................................................................................................................................................... 47

6.3.6 接口 ........................................................................................................................................................................... 47

6.4 可移植的字符串操作函数 .............................................................................................................................................. 48

6.4.1 接口 ........................................................................................................................................................................... 48

6.4.2 接口 ........................................................................................................................................................................... 48

6.5 区域无关的字符串操作函数 .......................................................................................................................................... 48

6.5.1 接口 ........................................................................................................................................................................... 48

6.6 IPv6 辅助和兼容性函数.................................................................................................................................................. 48

6.6.1 接口 ........................................................................................................................................................................... 48

6.6.2 接口 ........................................................................................................................................................................... 49

6.6.3 接口 ........................................................................................................................................................................... 49

6.7 结构体可移植性函数 ..................................................................................................................................................... 50

6.7.1 接口 ........................................................................................................................................................................... 50

6.8 安全随机数发生器 ........................................................................................................................................................ 50

6.8.1 接口 ........................................................................................................................................................................... 50

6.8.2 接口 ........................................................................................................................................................................... 50

7 bufferevent：概念和入门(Ref6_bufferevent.mht) ................................................................................................................. 51

7.1 bufferevent 和 evbuffer................................................................................................................................................. 51

7.2 回调和水位 ................................................................................................................................................................... 52

7.3 延迟回调 ...................................................................................................................................................................... 52

7.4 bufferevent 的选项标志 ................................................................................................................................................. 53

7.5 与基于套接字的 bufferevent 一起工作 .......................................................................................................................... 53

7.5.1 创建基于套接字的 bufferevent ................................................................................................................................... 53

7.5.2 在基于套接字的 bufferevent 上启动连接..................................................................................................................... 54

7.5.3 通过主机名启动连接 .................................................................................................................................................. 55

7.6 通用 bufferevent 操作 .................................................................................................................................................. 57

7.6.1 释放 bufferevent ........................................................................................................................................................ 57

7.6.2 操作回调、水位和启用/禁用 ...................................................................................................................................... 58

7.6.3 操作 bufferevent 中的数据.......................................................................................................................................... 61

7.6.4 读写超时 .................................................................................................................................................................... 64

7.6.5 对 bufferevent 发起清空操作 ...................................................................................................................................... 64

7.7 类型特定的 bufferevent 函数 ........................................................................................................................................ 65

7.7.1 接口 ........................................................................................................................................................................... 65

7.7.2 接口 ........................................................................................................................................................................... 65

7.7.3 接口 ........................................................................................................................................................................... 65

7.7.4 接口........................................................................................................................................................................... 66

7.8 手动锁定和解锁 ............................................................................................................................................................ 66

7.8.1 接口 ........................................................................................................................................................................... 66

7.9 已废弃的 bufferevent 功能 ........................................................................................................................................... 66

7.9.1 接口 ........................................................................................................................................................................... 67

7.9.2 接口 ........................................................................................................................................................................... 67

7.10 Bufferevent：高级话题(Ref7_evbuffer.mht) .................................................................................................................. 68

7.10.1 成对的 bufferevent ................................................................................................................................................... 68

7.10.2 过滤 bufferevent ...................................................................................................................................................... 69

7.10.3 限制每次最大读/写 size............................................................................................................................................. 70

7.10.4 bufferevent 和速率限制 ............................................................................................................................................. 70

7.10.5 bufferevent 和 SSL..................................................................................................................................................... 74

8 evbuffer:缓冲 IO 实用功(Ref7_evbuffer.mht) ....................................................................................................................... 80

8.1 创建和释放 evbuffer..................................................................................................................................................... 80

8.1.1 接口 ........................................................................................................................................................................... 80

8. 2 evbuffer 与线程安全 ..................................................................................................................................................... 80

8.2.1 接口 ........................................................................................................................................................................... 80

8.3 检查 evbuffer .............................................................................................................................................................. 81

8.3.1 接口 ........................................................................................................................................................................... 81

8.3.2 接口 ........................................................................................................................................................................... 81

8.4 向 evbuffer 添加数据：基础 ......................................................................................................................................... 81

8.4.1 接口 ........................................................................................................................................................................... 81

8.4.2 接口 ........................................................................................................................................................................... 82

8.4.3 接口 ........................................................................................................................................................................... 82

8.4.4 示例 ........................................................................................................................................................................... 82

8.5 将数据从一个 evbuffer 移动到另一个 ........................................................................................................................... 82

8.5.1 接口 ........................................................................................................................................................................... 82

8.6 添加数据到 evbuffer 前面............................................................................................................................................. 83

8.6.1 接口 ........................................................................................................................................................................... 83

8.7 重新排列 evbuffer 的内部布局...................................................................................................................................... 83

8.7.1 接口 ........................................................................................................................................................................... 83

8.7.2 示例 ........................................................................................................................................................................... 83

8.7.3 提示 ........................................................................................................................................................................... 84

8.8 从 evbuffer 中移除数据 ................................................................................................................................................ 84

8.8.1 接口 ........................................................................................................................................................................... 84

8.9 从 evbuffer 中复制出数据............................................................................................................................................. 85

8.9.1 接口 ........................................................................................................................................................................... 85

8.9.2 示例 ........................................................................................................................................................................... 85

8.10 面向行的输入 ............................................................................................................................................................. 86

8.10.1 接口 ......................................................................................................................................................................... 86

8.10.2 示例 ......................................................................................................................................................................... 87

8.11 在 evbuffer 中搜索 ..................................................................................................................................................... 87

8.11.1 接口 ......................................................................................................................................................................... 87

8.11.2 接口 ......................................................................................................................................................................... 88

8.11.3 接口 ......................................................................................................................................................................... 88

8.12 检测数据而不复制 ...................................................................................................................................................... 89

8.12.1 接口 ......................................................................................................................................................................... 89

8.12.2 示例 ......................................................................................................................................................................... 90

8.12.3 注意 ......................................................................................................................................................................... 91

8.13 直接向 evbuffer 添加数据 ........................................................................................................................................... 91

8.13.1 接口 ......................................................................................................................................................................... 92

8.13.2 提示和警告 .............................................................................................................................................................. 92

8.13.3 示例 ......................................................................................................................................................................... 92

8.13.4 不好的示例 .............................................................................................................................................................. 93

8.14 使用 evbuffer 的网络 IO............................................................................................................................................. 94

8.14.1 接口 ......................................................................................................................................................................... 94

8.15 evbuffer 和回调........................................................................................................................................................... 94

8.15.1 接口 ......................................................................................................................................................................... 95

8.15.2 接口 ......................................................................................................................................................................... 95

8.15.3 示例 ......................................................................................................................................................................... 95

8.15.4 接口 ......................................................................................................................................................................... 96

8.15.5 接口 ......................................................................................................................................................................... 97

8.16 为基于 evbuffer 的 IO 避免数据复制 ......................................................................................................................... 97

8.16.1 接口 ......................................................................................................................................................................... 97

8.16.2 示例 ........................................................................................................................................................................ 97

8.17 添加文件到 evbuffer ................................................................................................................................................... 98

8.17.1 接口 ......................................................................................................................................................................... 99

8.17.2 警告 ......................................................................................................................................................................... 99

8.18

精细控制

file segments

................................................................................................................................................ 99

8.18.1 接口 ......................................................................................................................................................................... 99

8.18.2 接口 ....................................................................................................................................................................... 100

8.19 通过引用添加 evbuffer 到另一个 evbuffer .................................................................................................................. 100

8.19.1 接口 ....................................................................................................................................................................... 100

8.20 让 evbuffer 只能添加或者只能移除 ........................................................................................................................... 101

8.20.1 接口 ....................................................................................................................................................................... 101

8.21 废弃的 evbuffer 函数 ................................................................................................................................................ 101

8.21.1 废弃的接口 ............................................................................................................................................................ 101

8.21.2 废弃的接口 ............................................................................................................................................................ 102

9 连接监听器：接受 TCP 连接(Ref8_listener.mht) ............................................................................................................... 102

9.1 创建和释放 evconnlistener ......................................................................................................................................... 102

9.1.1 接口 ......................................................................................................................................................................... 102

9.1.2 连接监听回调 ........................................................................................................................................................... 104

9.2 启用和禁用 evconnlistener ......................................................................................................................................... 104

9.2.1 接口 ......................................................................................................................................................................... 104

9.3 调整 evconnlistener 的回调函数 ................................................................................................................................. 104

9.3.1 接口 ......................................................................................................................................................................... 104

9.4 检测 evconnlistener ................................................................................................................................................... 105

9.4.1 接口 ......................................................................................................................................................................... 105

9.5 侦测错误 ................................................................................................................................................................... 105

9.5.1 接口.......................................................................................................................................................................... 105

9.6 示例：回显服务器 ...................................................................................................................................................... 105

10 使用 libevent 的 DNS:高层和底层功能(Ref9_dns.mht).................................................................................................... 107

10.1 预备：可移植的阻塞式名字解析 ............................................................................................................................... 108

10.1.1 接口 ....................................................................................................................................................................... 108

10.1.2 示例：解析主机名，建立阻塞的连接 ...................................................................................................................... 111

10.2 使用 evdns_getaddrinfo()的非阻塞式名字解析 .......................................................................................................... 112

10.2.1 接口 ....................................................................................................................................................................... 112

10.2.2 示例:使用 evdns_getaddrinfo()的非阻塞查询............................................................................................................. 113

10.3 创建和配置 evdns_base ............................................................................................................................................ 115

10.3.1 接口 ....................................................................................................................................................................... 115

10.3.2 使用系统配置初始化 evdns .................................................................................................................................... 116

10.3.3 手动配置 evdns ...................................................................................................................................................... 118

10.3.4 库端配置 ................................................................................................................................................................ 119

10.4 底层 DNS 接口 ......................................................................................................................................................... 119

10.4.1 缺少的特征 ............................................................................................................................................................ 120

10.4.2 接口 ....................................................................................................................................................................... 120

10.4.3 DNS 错误码............................................................................................................................................................. 121

10.4.4 接口 ....................................................................................................................................................................... 122

10.5 挂起 DNS 客户端操作，更换名字服务器 ................................................................................................................... 122

10.6 DNS 服务器接口........................................................................................................................................................ 122

10.6.1 创建和关闭 DNS 服务器接口 .................................................................................................................................. 122

10.6.2 检测 DNS 请求 ....................................................................................................................................................... 123

10.6.3 响应 DNS 请求 ....................................................................................................................................................... 124

10.7 DNS 服务器示例......................................................................................................................................................... 126

10.8 废弃的 DNS 接口 ...................................................................................................................................................... 128

前言

(Ref0_meta.html )

Libevent 是用于编写高速可移植非阻塞 IO 应用的库