server4.c

linux的程序设计第二版 是学习LINUX下程序设计的好教程哦

/*  This program, server4.c, begins in similar vein to our last server,
    with the notable addition of an include for the signal.h header file.
    The variables and the procedure of creating and naming a socket are the same.  */

#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <netinet/in.h>
#include <signal.h>
#include <unistd.h>

int main()
{
    int server_sockfd, client_sockfd;
    int server_len, client_len;
    struct sockaddr_in server_address;
    struct sockaddr_in client_address;

    server_sockfd = socket(AF_INET, SOCK_STREAM, 0);

    server_address.sin_family = AF_INET;
    server_address.sin_addr.s_addr = htonl(INADDR_ANY);
    server_address.sin_port = htons(9734);
    server_len = sizeof(server_address);
    bind(server_sockfd, (struct sockaddr *)&server_address, server_len);

/*  Create a connection queue, ignore child exit details and wait for clients.  */

    listen(server_sockfd, 5);

    signal(SIGCHLD, SIG_IGN);

    while(1) {
        char ch;

        printf("server waiting\n");

/*  Accept connection.  */

        client_len = sizeof(client_address);
        client_sockfd = accept(server_sockfd, 
            (struct sockaddr *)&client_address, &client_len);

/*  Fork to create a process for this client and perform a test to see
    whether we're the parent or the child.  */

        if(fork() == 0) {

/*  If we're the child, we can now read/write to the client on client_sockfd.
    The five second delay is just for this demonstration.  */

            read(client_sockfd, &ch, 1);
            sleep(5);
            ch++;
            write(client_sockfd, &ch, 1);
            close(client_sockfd);
            exit(0);
        }

/*  Otherwise, we must be the parent and our work for this client is finished.  */

        else {
            close(client_sockfd);
        }
    }
}