《UNIX網絡編程》中第一個timer_server的例子

 1.配置環境

    在這裏下載unpv13e.tar.gz，其中包含了《UNIX網絡編程》第一卷的源代碼。假設將其移到~/Unix/Network/目錄下，以下爲配置過程（假設當前目錄爲下載目錄）：

    mv ./unpv13e.tar.gz ~/Unix/Network

    cd ~/Unix/Network

    tar -zxvf unpv13e.tar.gz

    cd unpv13e

    ./configure

    cd lib

    make

    cd ../                  #back to unpv13e/

    cp libunp.a /usr/lib

    cp libunp.a /usr/lib64

    cd ../                  #back to Network/

    cp ./unpv13e/lib/unp.h ./

    cp ./unpv13e/config.h ./

    vi unp.h #使用vi將unp.h中的 #include "../config.h"改爲#include "./config.h"

    mkdir timer_server

    cd timer_server

2.編寫代碼    

 編寫服務端代碼：

#include "../unp.h"

int main(int argc,char *argv[])
{
    int listenfd,connfd;
    struct sockaddr_in servaddr;
    char buff[MAXLINE];
    time_t ticks;
    listenfd = Socket(AF_INET,SOCK_STREAM,0);
    bzero(&servaddr,sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port=htons(13);
    Bind(listenfd,(SA*)&servaddr,sizeof(servaddr));
    Listen(listenfd,LISTENQ);
    for(;;)
    {
        connfd = Accept(listenfd,(SA*)NULL,NULL);
        ticks = time(NULL);
        snprintf(buff,sizeof(buff),"%.24s\r\n",ctime(&ticks));
        Write(connfd,buff,strlen(buff));
        Close(connfd);
    }
    return 0;
}

      編寫客戶端代碼：

#include "../unp.h"

int main(int argc,char *argv[])
{
    int socketfd,n;
    char recvline[MAXLINE+1];
    struct sockaddr_in servaddr;
    if(argc != 2)
        err_quit("Usage:%s <IP Address>",argv[0]);
    if( (socketfd = socket(AF_INET,SOCK_STREAM,0)) <0 )
        err_sys("socket error");
    bzero(&servaddr,sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(13);
    if( inet_pton(AF_INET,argv[1],&servaddr.sin_addr) <= 0)
        err_quit("inet_pton error for %s .",argv[0]);
    if(connect(socketfd,(SA*)&servaddr,sizeof(servaddr))<0)
        err_sys("connecting error.");
    while( (n = read(socketfd,recvline,MAXLINE))>0){
        recvline[n] = 0;
        if(fputs(recvline,stdout) == EOF)
            err_sys("read error");
    }
    if(n<0)
        err_sys("read error");
    return 0;
}

         編譯運行：

$gcc server.c -o server -lunp
$gcc client.c -o client -lunp
$./server &
$./client 192.168.101.71
Mon Jul 16 17:37:45 2012
$./client 192.168.101.71
Mon Jul 16 17:37:47 2012
$./client 192.168.101.71
Mon Jul 16 17:37:47 2012
$./client 192.168.101.71
Mon Jul 16 17:37:49 2012

      在讀的時候有一個小技巧，就是使用循環的方式去讀套接口中的數據而不是隻讀一次，這是由於需要的數據可能分成多節傳過來。下面的代碼將展示這一點：

#include "../unp.h"

int main(int argc,char *argv[])
{
    int socketfd,n;
    char recvline[MAXLINE+1];
    struct sockaddr_in servaddr;
    if(argc != 2)
        err_quit("Usage:%s <IP Address>",argv[0]);
    if( (socketfd = socket(AF_INET,SOCK_STREAM,0)) <0 )
        err_sys("socket error");
    bzero(&servaddr,sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(13);
    if( inet_pton(AF_INET,argv[1],&servaddr.sin_addr) <= 0)
        err_quit("inet_pton error for %s .",argv[0]);
    if(connect(socketfd,(SA*)&servaddr,sizeof(servaddr))<0)
        err_sys("connecting error.");
    int counter = 0;
    while( (n = read(socketfd,recvline,MAXLINE))>0){
        recvline[n] = 0;
        if(fputs(recvline,stdout) == EOF)
            err_sys("read error");
        counter++;
    }
    printf("read operation :%d\n",counter);
    if(n<0)
        err_sys("read error");
    return 0;
}

        在循環中加入計數代碼，用來統計計數的次數。然後我們將服務器端的代碼改爲for循環的形式：

#include "../unp.h"

#include<string.h>
int main(int argc,char *argv[])
{
    int listenfd,connfd;
    struct sockaddr_in servaddr;
    char buff[MAXLINE];
    time_t ticks;
    listenfd = Socket(AF_INET,SOCK_STREAM,0);
    bzero(&servaddr,sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port=htons(13);
    Bind(listenfd,(SA*)&servaddr,sizeof(servaddr));
    Listen(listenfd,LISTENQ);
    for(;;)
    {
        connfd = Accept(listenfd,(SA*)NULL,NULL);
        ticks = time(NULL);
        snprintf(buff,sizeof(buff),"%.24s\r\n",ctime(&ticks));
        int i = 0;
        int len = strlen(buff);
        for(i=0;i<len;i++)
            Write(connfd,&buff[i],sizeof(char));
        Close(connfd);
    }
    return 0;
}

        下面爲運行效果：

         

$ ./client 192.168.101.71
Mon Jul 16 21:24:05 2012
read operation :4
$ ./client 192.168.101.71
Mon Jul 16 21:24:05 2012
read operation :4
$ ./client 192.168.101.71
Mon Jul 16 21:24:05 2012
read operation :3
$ ./client 192.168.101.71
Mon Jul 16 21:24:06 2012
read operation :4
$ ./client 192.168.101.71
Mon Jul 16 21:24:06 2012
read operation :3
$ ./client 192.168.101.71
Mon Jul 16 21:24:07 2012
read operation :5