// multi_thread_client.c 

#include <netinet/in.h>    // for sockaddr_in
#include <sys/types.h>    // for socket
#include <sys/socket.h>    // for socket
#include <stdio.h>        // for printf
#include <stdlib.h>        // for exit
#include <string.h>        // for bzero
#include <pthread.h>
#include <sys/errno.h>    // for errno

#define HELLO_WORLD_SERVER_PORT    6666 
#define BUFFER_SIZE 1024

char * server_IP = NULL;

void * talk_to_server(void * thread_num)
{
    //設(shè)置一個(gè)socket地址結(jié)構(gòu)client_addr,代表客戶機(jī)internet地址, 端口
    struct sockaddr_in client_addr;
    bzero(&client_addr,sizeof(client_addr)); //把一段內(nèi)存區(qū)的內(nèi)容全部設(shè)置為0
    client_addr.sin_family = AF_INET;    //internet協(xié)議族
    client_addr.sin_addr.s_addr = htons(INADDR_ANY);//INADDR_ANY表示自動(dòng)獲取本機(jī)地址
    client_addr.sin_port = htons(0);    //0表示讓系統(tǒng)自動(dòng)分配一個(gè)空閑端口
    //創(chuàng)建用于internet的流協(xié)議(TCP)socket,用client_socket代表客戶機(jī)socket
    int client_socket = socket(AF_INET,SOCK_STREAM,0);
    if( client_socket < 0)
    {
        printf("Create Socket Failed!\n");
        exit(1);
    }
    //把客戶機(jī)的socket和客戶機(jī)的socket地址結(jié)構(gòu)聯(lián)系起來
    if( bind(client_socket,(struct sockaddr*)&client_addr,sizeof(client_addr)))
    {
        printf("Client Bind Port Failed!\n"); 
        exit(1);
    }

    //設(shè)置一個(gè)socket地址結(jié)構(gòu)server_addr,代表服務(wù)器的internet地址, 端口
    struct sockaddr_in server_addr;
    bzero(&server_addr,sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    if(inet_aton(server_IP,&server_addr.sin_addr) == 0) //服務(wù)器的IP地址來自程序的參數(shù)
    {
        printf("Server IP Address Error!\n");
        exit(1);
    }
    server_addr.sin_port = htons(HELLO_WORLD_SERVER_PORT);
    socklen_t server_addr_length = sizeof(server_addr);
    //向服務(wù)器發(fā)起連接,連接成功后client_socket代表了客戶機(jī)和服務(wù)器的一個(gè)socket連接
    if(connect(client_socket,(struct sockaddr*)&server_addr, server_addr_length) < 0)
    {
        printf("Can Not Connect To %s!\n",server_IP);
        exit(1);
    }

    char buffer[BUFFER_SIZE];
    bzero(buffer,BUFFER_SIZE);
    //從服務(wù)器接收數(shù)據(jù)到buffer中
    int length = recv(client_socket,buffer,BUFFER_SIZE,0);
    if(length < 0)
    {
        printf("Recieve Data From Server %s Failed!\n", server_IP);
        exit(1);
    }
    printf("From Server %s :\t%s",server_IP,buffer);

    bzero(buffer,BUFFER_SIZE);
    sprintf(buffer,"Hello, World! From Client Thread NUM :\t%d\n",(int)thread_num);
    //向服務(wù)器發(fā)送buffer中的數(shù)據(jù)
    send(client_socket,buffer,BUFFER_SIZE,0);
    //關(guān)閉socket
    close(client_socket);
    pthread_exit(NULL);
}

int main(int argc, char **argv)
{
    if (argc != 2)
    {
        printf("Usage: ./%s ServerIPAddress\n",argv[0]);
        exit(1);
    }
    server_IP = argv[1];
    
    pthread_t child_thread;
    pthread_attr_t child_thread_attr;
    pthread_attr_init(&child_thread_attr);
    pthread_attr_setdetachstate(&child_thread_attr,PTHREAD_CREATE_DETACHED);
    int i=0;
    for(i=0; i<10000; i++)
    {
        if( pthread_create(&child_thread,&child_thread_attr,talk_to_server,    (void *)i) < 0 )
            printf("pthread_create Failed : %s\n",strerror(errno));
    }
    return 0;
}