Linux下的 socket api学习

 // File Name: socket.cpp
    // Author: simon li
    // Created Time: 2019年09月23日 星期一 17时01分07秒
    
    #include<vector>
    #include<list>
    #include<map>
    #include<set>
    #include<deque>
    #include<stack>
    #include<bitset>
    #include<algorithm>
    #include<functional>
    #include<numeric>
    #include<utility>
    #include<sstream>
    #include<iostream>
    #include<iomanip>
    #include<cstdio>
    #include<cmath>
    #include<cstdlib>
    #include<cstring>
    #include<ctime>
    #include<netinet/in.h>
    #include<bits/socket.h>
    #include<sys/un.h>
    #include<arpa/inet.h>
    #include<sys/types.h>
    #include<sys/socket.h>
    #include<signal.h>
    #include<unistd.h>
    #include<assert.h>
    using namespace std;
    //Linux提供了一以下4个函数来完成主机字节序和网络字节序之间的转换
    unsigned long int htonl(unsigned long int hostlong);
    unsigned short int htons(unsigned short int hostshort);
    unsigned long int ntohl(unsigned long int netlong);
    unsigned short int ntohs(unsigned short int netshort);
    
    
    /*int inet_pton(int af , const char* src,void* dst);//将src的点十分禁止转换为网络字节序，并存入dst中
    const char* inet_ntop(int af, const void* src, char* dst,socklen_t cnt);
    //将网络字节数af转换成点分十进制的IPV4地址src到dst中
    static bool stop = false;
    
    int socket(int domain, int type,int protocol);
    //创建socket。domain采用的协议：PF_INET或者PF_INET6,type 服务类型有：SOCK_STREAM和SOCK_UGRAM,
    //protocol采用默认协议
    
    int bind (int sockfd,const struct sockaddr* my_addr,socklen_t addrlen);
    //命名socket,将 my_addr所指的socket地址分配给sockfd文件描述符，addrle指出该cocket地址长度
    int
    struct sockaddr//表示sokcet的地址的结构体
    {
        sa_family_t sa_family;//地址族协议类型
        char sa_data[13];
    };
    
    struct sockaddr_storage//为了存储更多的协议族，
    {
        sa_family_t sa_family;//地址族协议类型
        unsigned long int _ss_alig;
        char _ss_padding[128 - sizeof(_ss_align)];
    };
    struct sokaddr_un//unix专用的socket地址
    {
        sa_family_t sin_falmily;//地址族：AF_UNIX
        char sun_path[108];//文件路径
    };
    
    struct sockaddr_in//IPV4
    {
        sa_family_t sin_family;//地址族协议族：AF_INET
        u_int16_t sin_port;//端口号：用网络字节序
        struct in_addr sin_addr;//IPV4地址结构体
    };
    struct in_addr
    {
        u_int32_t s_addr;
    };
    struct sockaddr_in6
    {
        sa_family_t sin6_family;
        u_int16_t sin6_port;
        u_int32_t sin6_flowinfo;
        struct in6_addr sin6_addr;
        u_int32_t sin6_scope_id;
    };
    struct in6_addr
    {
        unsigned char sa_addr[16];
    };*/
    //监听socket
    #include<sys/socket.h>
    int listen (int sockfd,int backlog);
    //sockfd参数指定被监听的socket，backlog参数提示内核监听队列的最大长度
    
    static bool stop = false;
    
    static void handle(int sig)//SIGTERM信号的处理函数，触发时结束住程序中的循环
    {
        stop = true;
    }
    
    int main(int argc,char* argv[]){
        signal(SIGTERM,handle);
        if (argc <= 3)
        {
            cout<<"usage:"<<basename(argv[0])<<"ip_address port_number backlog"<<endl;
            return 1;
        }
        const char* ip = argv[1];//IP地址
        int port = atoi(argv[2]);//端口号
        int backlog = atoi (argv[3]);//内核监听队列最大长度,将字符转化成整形
        int sock = socket (PF_INET,SOCK_STREAM,0);//创建socket
        assert(sock >= 0);
        struct sockaddr_in address;
        bzero(&address, sizeof(address));
        address.sin_family = AF_INET;//选择协议簇类型IPV4
        inet_pton(AF_INET,ip,&address.sin_addr);
        //点十分进制的ipv4地址转换成网络字节序证书存储与 address中
        address.sin_port = htons(port);
        int ret = bind(sock,(struct sockaddr*)&address,sizeof(address));//创建socket绑定IP弟子和端口号
        assert(ret!= -1);
        ret = listen(sock,backlog);//监听该端口的数据，并确定监听队列长度
        assert(ret != -1);
        while(!stop)
        {
            sleep(1);
    
        }
    
        close(sock);
    
    return 0;
    }