socket编程-- test select

client.cc

/*
 * client.cc
 *
 *  Created on: 2012-1-17
 *      Author: simondu
 */

#include "head.h"

#define MAXLINE 80
#define SERV_PORT 8000

int main(int argc, char *argv[])
{
    struct sockaddr_in servaddr;
    char buf[MAXLINE];
    int sockfd, n;
    char *str;

    printf("starting... \n");
    if (argc != 2) {
        fputs("usage: ./client message\n", stderr);
        exit(1);
    }
    str = argv[1];
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    bzero(&servaddr, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    inet_pton(AF_INET, "127.0.0.1", &servaddr.sin_addr);
    servaddr.sin_port = htons(SERV_PORT);
    connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr));

    while (fgets(buf, MAXLINE, stdin) != NULL) {
            write(sockfd, buf, strlen(buf));
            n = read(sockfd, buf, MAXLINE);
            if (n == 0)
                printf("the other side has been closed.\n");
            else
                //Write(STDOUT_FILENO, buf, n);
                printf("%s\n",buf);
        }

    close(sockfd);
    return 0;
}

server.cc

/*
 * server.cc
 *
 *  Created on: 2012-1-17
 *      Author: simondu
 */
#include "head.h"

#define MAXLINE 80
#define SERV_PORT 8000
int main(void )
{
    int i, maxi, maxfd, listenfd, connfd, sockfd;
    int nready, client[FD_SETSIZE];
    ssize_t n;
    fd_set rset, allset;
    char buf[MAXLINE];
    char str[INET_ADDRSTRLEN];
    socklen_t cliaddr_len;
    struct sockaddr_in    cliaddr, servaddr;

    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(SERV_PORT);

    bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr));

    listen(listenfd, 20);

    maxfd = listenfd;        /* initialize */
    maxi = -1;            /* index into client[] array */
    for (i = 0; i < FD_SETSIZE; i++)
        client[i] = -1;    /* -1 indicates available entry */
    FD_ZERO(&allset);
    FD_SET(listenfd, &allset);
    printf("Starting ... \n");
    for ( ; ; ) {
        rset = allset;    /* structure assignment */
        nready = select(maxfd+1, &rset, NULL, NULL, NULL);
        if (nready < 0)
        {
            printf("select error");
            exit(1);
        }

        if (FD_ISSET(listenfd, &rset)) { /* new client connection */
            cliaddr_len = sizeof(cliaddr);
            connfd = accept(listenfd, (struct sockaddr *)&cliaddr, &cliaddr_len);

            printf("received from %s at PORT %d\n",
                   inet_ntop(AF_INET, &cliaddr.sin_addr, str, sizeof(str)),
                   ntohs(cliaddr.sin_port));

            for (i = 0; i < FD_SETSIZE; i++)
                if (client[i] < 0) {
                    client[i] = connfd; /* save descriptor */
                    break;
                }

            if (i == FD_SETSIZE) {
                fputs("too many clients\n", stderr);
                exit(1);
            }

            FD_SET(connfd, &allset);    /* add new descriptor to set */
            if (connfd > maxfd)
                maxfd = connfd; /* for select */
            if (i > maxi)
                maxi = i;    /* max index in client[] array */

            if (--nready == 0)
                continue;    /* no more readable descriptors */
        }

        for (i = 0; i <= maxi; i++) {    /* check all clients for data */
            if ( (sockfd = client[i]) < 0)
            {
                printf("sockfd = client[i] = %d\n",sockfd);
                continue;
            }
            if (FD_ISSET(sockfd, &rset)) {
                if ( (n = read(sockfd, buf, MAXLINE)) == 0) {
                    /* connection closed by client */
                    close(sockfd);
                    FD_CLR(sockfd, &allset);
                    client[i] = -1;
                } else {
                    int j;
                    for (j = 0; j < n; j++)
                        buf[j] = toupper(buf[j]);
                    int rettest = write(sockfd, buf, n);
                    printf("%d\n",rettest);
                }
                if (--nready == 0)
                    break;    /* no more readable descriptors */
            }
        }
    }

}

test