linux tcp 服务器客户端发送接收数据(例一)

/*************************************************************************
 Author: Wan Xinshuo
 Created Time: 2009年04月14日 星期二 11时32分34秒
 File Name: server01.c
 Description:
 ************************************************************************/

#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include

#define BACKLOG 10 // how many pending connections queue will hold

void sigchld_handler(int s)
{
    while(waitpid(-1, NULL, WNOHANG) > 0);//参考：me
}

int main(int argc, char *argv[] )
{
    int sockfd, new_fd; // listen on sock_fd, new connection on new_fd

    struct sockaddr_in my_addr; // my address information

    struct sockaddr_in their_addr; // connector's address information

    socklen_t sin_size;
    struct sigaction sa;
    int yes=1;
    char buff[100];
    int nrecv;

    if( argc != 2 )
    {
         fprintf(stderr, "usage: server port\n Ex:\n$ ./server01 8888\n");
         exit(1);
    }
    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
        perror("socket");
        exit(1);
    }

    if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1) {
        perror("setsockopt");
        exit(1);
    }

    my_addr.sin_family = AF_INET; // host byte order

    my_addr.sin_port = htons(atoi(argv[1])); // short, network byte order

    my_addr.sin_addr.s_addr = INADDR_ANY; // automatically fill with my IP

    memset(my_addr.sin_zero, '\0', sizeof my_addr.sin_zero);

    if (bind(sockfd, (struct sockaddr *)&my_addr, sizeof my_addr) == -1) {
        perror("bind");
        exit(1);
    }

    if (listen(sockfd, BACKLOG) == -1) {
        perror("listen");
        exit(1);
    }

    sa.sa_handler = sigchld_handler; // reap all dead processes

    sigemptyset(&sa.sa_mask);
    sa.sa_flags = SA_RESTART;
    if (sigaction(SIGCHLD, &sa, NULL) == -1) {
        perror("sigaction");
        exit(1);
    }

    while(1) { // main accept() loop

        sin_size = sizeof their_addr;
        if ((new_fd = accept(sockfd, (struct sockaddr *)&their_addr, &sin_size)) == -1) {
            perror("accept");
            continue;
        }
        printf("server: got connection from %s : %d \n",
            inet_ntoa(their_addr.sin_addr), their_addr.sin_port);

        if (!fork()) { // this is the child process

            close(sockfd); // child doesn't need the listener
        while(1)
        {
        if (send(new_fd, "Hello,This is server message!", strlen("Hello,This is server message!"), 0) == -1)
        {
            perror("send");
            continue;
        }
        if ( (nrecv =  recv( new_fd, buff, 100, 0 )) > 0  )
        {
            buff[nrecv] = '\0';
            printf(" buff = %s \n", buff );
        }
        else if( nrecv == 0 )
        {
            printf(" Remote client close\n");
            break;
        }
        sleep(1);
        }
            close(new_fd);
            exit(0);
        }
        close(new_fd); // parent doesn't need this

    }

    return 0;
}




/*************************************************************************
 Author: Wan Xinshuo
 Created Time: 2009年04月14日 星期二 11时33分18秒
 File Name: client01.c
 Description:
 ************************************************************************/

#include
#include
#include
#include
#include
#include
#include
#include
#include

#define MAXDATASIZE 100 // max number of bytes we can get at once


int main(int argc, char *argv[])
{
    int sockfd, numbytes;
    char buf[MAXDATASIZE];
    struct hostent *he;
    struct sockaddr_in their_addr; // connector'saddress information


     if (( argc == 1) || (argc==2) ) {
        fprintf(stderr,"usage: client hostname\nEx:\n$./client01 ip port\n");
        exit(1);
    }

    if ((he=gethostbyname(argv[1])) == NULL) { // get the host info

        herror("gethostbyname");
        exit(1);
    }

    if ((sockfd = socket(PF_INET, SOCK_STREAM, 0)) == -1) {
        perror("socket");
        exit(1);
    }

    their_addr.sin_family = AF_INET; // host byte order

    their_addr.sin_port = htons(atoi(argv[2])); // short, network byte order

    their_addr.sin_addr = *((struct in_addr *)he->h_addr);
    memset(their_addr.sin_zero, '\0', sizeof their_addr.sin_zero);

    if (connect(sockfd, (struct sockaddr *)&their_addr,
                                          sizeof their_addr) == -1) {
        perror("connect");
        exit(1);
    }
   
    while( 1 )
    {
    if(  send(sockfd, "hello, this is client message!", strlen("hello, this is client message!"), 0 ) == -1 )   
    {
        perror("send");
    }

    if ((numbytes=recv(sockfd, buf, MAXDATASIZE-1, 0)) == -1)
    {
        perror("recv");
    }
    else if( numbytes == 0 )
    {
        printf("Remote server has shutdown!\n");
        break;
    }

    buf[numbytes] = '\0';

    printf("Received: %s \n",buf);
    sleep(1);
    }

    close(sockfd);

    return 0;
}

编译:
gcc -o server01 server01.c
gcc -o client01 client01.c

运行:
$server01 8888
$client01  ip 8888  

注: "ip" 为 server01所在的ip

server端先Ctrl+c关闭程序,客户端收到0,正常退出!