参考：

1. libevent

使用第三方库我一般都偏爱最新的版本，libevent也是如此，所以我以 libevent-2.1.8-stable.tar.gz为例，在官网上可以下载。

编译、使用

./configuremake

头文件在include文件夹下，编译生成的动态库在.libs文件夹下。

使用时，需要包含头文件和连接libevent.so动态库。

2. 示例

2.1 TcpServer.h

#ifndef TCP_SERVER_H#define TCP_SERVER_Hstruct event_base;class TcpServer{public:    using callback = void(int, short, void*);    //typedef void (callback)(int, short, void*);public:    TcpServer(const int port);    ~TcpServer();    int Initialize();    int Start();    void Process();private:    int m_fd;    int m_port;    event_base* m_base;    callback *m_accept_callback;};#endif  // TCP_SERVER_H

2.2 TcpServer.cpp

#include "TcpServer.h"#include 
    
     #include 
     
      #include 
      
       #include 
       
        #include 
        
         #include 
         
          #include "libevent/event.h"void accept_cb(int fd, short events, void* arg){ struct sockaddr_in client; socklen_t len = sizeof(client); int sockfd = ::accept(fd, (struct sockaddr*)&client, &len ); if(sockfd < 0){ return; } /* 提取客户端IP地址 */ char szIP[64] = { 0 }; // 客户端IP地址 std::string strIP = inet_ntop(AF_INET, &client.sin_addr, szIP, sizeof(szIP)); printf("connect from client: %s\n", strIP.c_str()); TcpServer *pServer = static_cast
          
           (arg); pServer->Process(sockfd); close(sockfd); printf("close\n");}TcpServer::TcpServer(const int port): m_fd(-1), m_port(port), m_base(nullptr), m_accept_callback(nullptr) { m_accept_callback = accept_cb; }TcpServer::~TcpServer(){ close(m_fd);}int TcpServer::Initialize(){ m_fd = ::socket(AF_INET, SOCK_STREAM, 0); if( m_fd == -1 ) return -1; struct sockaddr_in sin; sin.sin_family = AF_INET; sin.sin_addr.s_addr = 0; sin.sin_port = htons(m_port); int flag = 1; socklen_t len = sizeof(flag); if(::setsockopt(m_fd, SOL_SOCKET, SO_REUSEADDR, &flag, len) < 0) { return -4; } if( ::bind(m_fd, (struct sockaddr *)&sin, sizeof(sin)) < 0 ) { return -2; } if( ::listen(m_fd, 10) < 0) { return -3; } return 0;}int TcpServer::Start(){ m_base = event_base_new(); if(nullptr == m_base) { return -4; } //添加监听客户端请求连接事件 struct event* ev_listen = event_new(m_base, m_fd, EV_READ | EV_PERSIST, m_accept_callback, this); event_add(ev_listen, NULL); event_base_dispatch(m_base); return 0;}void TcpServer::Process(int fd){ printf("process...\n"); char msg[4096]; int len = read(fd, msg, sizeof(msg) - 1); if( len <= 0 ) { printf("some error happen when read\n"); return ; } printf("%s",msg); if(strcmp(msg,"get stats") != 0) { // return; } // {'stat':'1', 'version':'${project.name}-V${project.version}-B${SVN.revision}'} char reply_msg[4096] = "{'stat':'1', 'version':'middleware-V1.0.0-B12965'}"; write(fd, reply_msg, strlen(reply_msg) );}
          
         
        
       
      
     
    

2.3 main.cpp

#include "TcpServer.h"// #include 
    
     #include 
     
      #include 
      
       using namespace std;int main(){    shared_ptr
       
         spServer = make_shared
        
         (999);    int ret = 0;    ret = spServer->Initialize();j    if (ret != 0){        std::cout<<"initialize failed "<
         
          <
          
           Start(); // while(true) // { // sleep(1); // } return 0;}
          
         
        
       
      
     
    

2.4 CMakeLists.txt

cmake_minimum_required(VERSION 2.6)project(demo)# 设置编译器（gcc/g++）set(CMAKE_CXX_COMPILER "g++")#设置Debug/Releaseset(CMAKE_BUILD_TYPE "Debug")# 设置编译选项set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -pthread -g -Wall")# 设置可执行二进制文件的目录set(EXECUTABLE_OUTPUT_PATH ${PROJECT_SOURCE_DIR}/bin)# 设置存放编译出来的库文件的目录set(LIBRARY_OUTPUT_PATH ${PROJECT_SOURCE_DIR}/lib)# 并把该目录设置为链接目录link_directories(${PROJECT_SOURCE_DIR}/lib)# 设定头文件目录include_directories(${PROJECT_SOURCE_DIR}/include)# 增加子文件夹（src路径是通过子文件夹形式添加）add_subdirectory(${PROJECT_SOURCE_DIR}/src)

# 编译静态、动态链接库add_library(TcpServer SHARED TcpServer.cpp)target_link_libraries(TcpServer libevent.so)# 编译可执行文件和设置链接库（注意顺序）add_executable(main main.cpp)target_link_libraries(main libTcpServer.so)

2.5 测试

可以通过curl命令来查看是否可以连接服务器

curl http://ip:port

或者telnet命令来检查

[root@thor ~]# telnet 127.0.0.1 999Trying 127.0.0.1...Connected to 127.0.0.1.Escape character is '^]'.get stats{'stat':'1', 'version':'middleware-V1.0.0-B12965'}Connection closed by foreign host.