libevent （二）初始化配置libevent上下文

文章目录

• ​​libevent 初始化配置(网络模式与默认特征)​​
• ​​在windows下使用IOCP(默认开启线程)​​

libevent 初始化配置：获取系统所支持的网络模型

libevent 初始化配置(网络模式与默认特征)

#include <iostream>
#include <event2/event.h>
#ifndef _WIN32
#include <signal.h>
#endif
using namespace std;



int main(int argc, char** argv) {
#if _WIN32
  //windowns 初始化socket库
  WSADATA wsa;
  WSAStartup(MAKEWORD(2, 2), &wsa);
#else
  //linux 忽略管道信号，发送数据给已关闭的socket
  if (signal(SIGPIPE, SIG_IGN) == SIG_ERR)
    return 1;
#endif

  //初始化配置libevent上下文

  //创建配置上下文
  event_config* conf = event_config_new();

  //显示支持的网络模式
  const char** methods = event_get_supported_methods();
  cout << "supported_methods:" << endl;
  for (int i = 0; methods[i]!=NULL; i++) {
    cout << "methods:" << methods[i] << endl;
  }
  
  event_base* base = event_base_new_with_config(conf);
  if (!base) {
    std::cerr << "event_base_new_with_config failed!" << std::endl;
    return -1;
  }
  std::cout << "event_base_new_with_config successfully!" << std::endl;

  cout << "=====================Default Feature=====================" << endl;
  //确认特征是否生效
  int feature = event_base_get_features(base);
  if (feature&EV_FEATURE_ET){
    cout << "EV_FEATURE_ET supported" << endl;
  }
  else
  {
    cout << "EV_FEATURE_ET not supported" << endl;
  }
  if (feature & EV_FEATURE_O1) {
    cout << "EV_FEATURE_O1 supported" << endl;
  }
  else
  {
    cout << "EV_FEATURE_O1 not supported" << endl;
  }
  if (feature & EV_FEATURE_FDS) {
    cout << "EV_FEATURE_FDS supported" << endl;
  }
  else
  {
    cout << "EV_FEATURE_FDS not supported" << endl;
  }
  if (feature & EV_FEATURE_EARLY_CLOSE) {
    cout << "EV_FEATURE_EARLY_CLOSE supported" << endl;
  }
  else
  {
    cout << "EV_FEATURE_EARLY_CLOSE not supported" << endl;
  }

  event_base_free(base);
  event_config_free(conf);

  return 0;
}

win10平台

linux平台

在windows下使用IOCP(默认开启线程)

#include <iostream>
#include <event2/event.h>
#include <event2/thread.h>
#include <event2/listener.h>
#ifndef _WIN32
#include <signal.h>
#endif
#define SPORT 5001

using namespace std;



void listen_cb(evconnlistener* ev, evutil_socket_t t, struct sockaddr* addr, int socklen, void *arg){
  cout << "listen_cb" << endl;
}



int main(int argc, char** argv) {
#if _WIN32
  //windowns 初始化socket库
  WSADATA wsa;
  WSAStartup(MAKEWORD(2, 2), &wsa);
#else
  //linux 忽略管道信号，发送数据给已关闭的socket
  if (signal(SIGPIPE, SIG_IGN) == SIG_ERR)
    return 1;
#endif

  //创建配置上下文
  event_config* conf = event_config_new();

  //显示支持的网络模式
  const char** methods = event_get_supported_methods();
  cout << "supported_methods:" << endl;
  for (int i = 0; methods[i]!=NULL; i++) {
    cout << "methods:" << methods[i] << endl;
  }
  
  //设置特征(设置了EV_FEATURE_FDS，其它特征就无法设置，windows中无效)
  // event_config_require_features(conf, EV_FEATURE_FDS); //不支持epoll

  //设置网络模型，使用select (不设置linux默认epoll)
  //event_config_avoid_method(conf, "epoll");
  //event_config_avoid_method(conf, "poll");


  //windows支持IOCP(默认开始线程池)
#if _WIN32
  event_config_set_flag(conf, EVENT_BASE_FLAG_STARTUP_IOCP);

  // 初始化IOCP的线程
  evthread_use_windows_threads();
  
  //设置CPU数量
  SYSTEM_INFO si;
  GetSystemInfo(&si);
  event_config_set_num_cpus_hint(conf, si.dwNumberOfProcessors);
#endif

  //初始化配置libevent上下文
  event_base* base = event_base_new_with_config(conf);
  if (!base) {
    std::cerr << "event_base_new_with_config failed!" << std::endl;
    base = event_base_new();
    if (!base){
      cout << "event_base_new failed!" << endl;
      return -1;
    }
  }
  std::cout << "event_base_new_with_config successfully!" << std::endl;

  //获取当前网络模型
  cout << "current method is: " << event_base_get_method(base) << endl;


  cout << "=====================Default Feature=====================" << endl;
  //确认特征是否生效
  int feature = event_base_get_features(base);
  if (feature&EV_FEATURE_ET){
    cout << "EV_FEATURE_ET supported" << endl;
  }
  else
  {
    cout << "EV_FEATURE_ET not supported" << endl;
  }
  if (feature & EV_FEATURE_O1) {
    cout << "EV_FEATURE_O1 supported" << endl;
  }
  else
  {
    cout << "EV_FEATURE_O1 not supported" << endl;
  }
  if (feature & EV_FEATURE_FDS) {
    cout << "EV_FEATURE_FDS supported" << endl;
  }
  else
  {
    cout << "EV_FEATURE_FDS not supported" << endl;
  }
  if (feature & EV_FEATURE_EARLY_CLOSE) {
    cout << "EV_FEATURE_EARLY_CLOSE supported" << endl;
  }
  else
  {
    cout << "EV_FEATURE_EARLY_CLOSE not supported" << endl;
  }

  sockaddr_in sin;
  memset(&sin, 0, sizeof(sin));
  sin.sin_family = AF_INET;
  sin.sin_port = htons(SPORT);


  evconnlistener* ev = evconnlistener_new_bind(base, listen_cb, base, 10,
    LEV_OPT_CLOSE_ON_FREE | LEV_OPT_REUSEABLE, 
    (sockaddr*)&sin, sizeof(sin));
  event_base_dispatch(base);

  evconnlistener_free(ev);
  event_base_free(base);
  event_config_free(conf);

  return 0;
}