poll 的例子

server:

/* * Pollserver.c * *  Created on: 2012-9-9 *      Author: sangerhoo */#include<sys/types.h>#include<ctype.h>#include<strings.h>#include<unistd.h>#include<sys/socket.h>#include<netinet/in.h>#include<netdb.h>#include<arpa/inet.h>#include<ctype.h>#include<errno.h>#include<sys/time.h>#include<stdio.h>#include<string.h>#include<sys/poll.h>#include<stdlib.h>#define LISTEN_QUEUE_NUM 5#define MAX_CONNECT 1024#define BUFFER_SIZE 256#define ECHO_PORT 2029static struct pollfd clipoll[MAX_CONNECT];int max = 0;/*initialize poll struct*/static void poll_init(){int i;for (i = 0; i < MAX_CONNECT; i++)clipoll[i].fd = -1;}/* find a unused pollfd struct if found then return its index else return -1*/static int poll_alloc(){int i;for (i = 0; i < MAX_CONNECT; i++){if (clipoll[i].fd < 0)return i;}return -1;}/*find used max index in pllfd*/static void update_max(){int i;max = 0;for (i = 0; i < MAX_CONNECT; i++){if (clipoll[i].fd > 0)max = i;}}/*free a pollfd when unused*/static int poll_free(int i){close(clipoll[i].fd);clipoll[i].fd = -1;clipoll[i].events = 0;clipoll[i].revents = 0;update_max();}/*  fill up pollfd with file descriptable  and event*/static int poll_set_item(int fd, uint32_t events){int i;if ((i = poll_alloc()) < 0)return -1;clipoll[i].fd = fd;clipoll[i].events = events;clipoll[i].revents = 0;if (i > max)max = i;return 0;}int main(int argc, char **argv){struct sockaddr_in servaddr, remote;int request_sock, new_sock;int nfound, i, bytesread;uint32_t addrlen;char buf[BUFFER_SIZE];/*setup socket*/if ((request_sock = socket(AF_INET, SOCK_STREAM, 0)) < 0){perror("socket");return -1;}/*fill up ip address structure*/memset(&servaddr, 0, sizeof(servaddr));servaddr.sin_family = AF_INET;servaddr.sin_addr.s_addr = INADDR_ANY;servaddr.sin_port = htons(ECHO_PORT);/*bind server ip address structure*/if (bind(request_sock, (struct sockaddr *) &servaddr, sizeof(servaddr)) <0){perror("bind");return -1;}/*listen client*/if (listen(request_sock, LISTEN_QUEUE_NUM) < 0){perror("listen");return -1;}poll_init();poll_set_item(request_sock, POLLIN);while (1){/*check whether ready file exist ?*/if ((nfound = poll(clipoll, max + 1, 500)) < 0){if (errno == EINTR){printf("interruptedb system call\n");continue;}perror("poll");return -1;}else if(nfound == 0){printf(".");fflush(stdout);continue;}/*check listen socket if ready or not ?*/if (clipoll[0].revents & (POLLIN | POLLERR)){addrlen = sizeof(remote);if ((new_sock =accept(request_sock, (struct sockaddr *) &remote,&addrlen)) < 0){perror("accept");return -1;}printf("connection fromm host %s,port %d, socket %d\r\n",inet_ntoa(remote.sin_addr), ntohs(remote.sin_port), new_sock);if (poll_set_item(new_sock, POLLIN) < 0)fprintf(stderr, "Too many connects\r\n");nfound--;}/*check communicating socket if ready or not ? */for (i = 1; i <= max && nfound > 0; i++){if (clipoll[i].fd >= 0 && clipoll[i].revents & (POLLIN | POLLERR)){nfound--;if((bytesread = read(clipoll[i].fd, buf, sizeof(buf) - 1)) < 0){perror("read");poll_free(i);continue;}if(bytesread == 0){fprintf(stderr, "server: end of file on %d\r\n", clipoll[i].fd);poll_free(i);continue;}buf[bytesread] = 0;printf("%s:%d bytes from %d :%s\n", argv[0], bytesread,clipoll[i].fd, buf);if (write(clipoll[i].fd, buf, bytesread) != bytesread){perror("echo");poll_free(i);continue;}}}}return 0;}

client:

/* * pollclient.c * *  Created on: 2012-9-9 *      Author: sangerhoo */#include<sys/types.h>#include<sys/socket.h>#include<sys/time.h>#include<netinet/in.h>#include<errno.h>#include<ctype.h>#include<netdb.h>#include<stdio.h>#include<string.h>#include<stdlib.h>#include<unistd.h>#include<sys/select.h>#include<sys/poll.h>#define RET_OK 0#define RET_ERR -1#define LISTEN_QUEUE_NUM 5#define BUFFER_SIZE 256#define ECHO_PORT   2029int main(int argc, char **argv){int sock;struct sockaddr_in servaddr;struct hostent *server;static struct pollfd cpoll[2];int nfound, bytesread;char buf[BUFFER_SIZE];if(argc < 2){fprintf(stderr, "usage %s hostname\n", argv[0]);return RET_ERR;}if((server = gethostbyname(argv[1])) == NULL){perror("gethostbyname. ");return RET_ERR;}/*setup socket*/if((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0){perror("socket");return -1;}/*fillup ip address structure*/memset(&servaddr, 0, sizeof(servaddr));servaddr.sin_family = AF_INET;servaddr.sin_addr.s_addr = *(uint32_t *) server->h_addr;servaddr.sin_port = htons((uint16_t) ECHO_PORT);/*connect to server*/if(connect(sock, (struct sockaddr *) &servaddr, sizeof(servaddr)) < 0){perror("connect");return -1;}/*fill up poll struct*/cpoll[0].fd = fileno(stdin);cpoll[0].events = POLLIN;cpoll[1].fd = sock;cpoll[1].events = POLLIN;while (1){if ((nfound = poll(cpoll, 2, -1)) < 0){if (errno == EINTR){fprintf(stderr, "interruptedb system call\n");continue;}perror("select");exit(1);}/*check stdin is ready or not ? */if (cpoll[0].revents & (POLLIN | POLLERR)){if(fgets(buf, sizeof(buf), stdin) == NULL){if (ferror(stdin)){perror("stdin");return -1;}return 0;}/*write to socket*/if (write(sock, buf, strlen(buf)) < 0){perror("write");return -1;}}/*check socket is ready or not ? */if(cpoll[1].revents & (POLLIN | POLLERR)){/*read from socket*/if((bytesread = read(sock, buf, sizeof(buf))) < 0){perror("read");exit(1);}else if(bytesread == 0){fprintf(stderr, "server disconnect\n");exit(0);}buf[bytesread] = 0;printf("%s\n", buf);}}return 0;}

运行结果是：

root@hdp3:/media/sf_workspace/sangerhoo/unp# ..../................................................................................connection fromm host 127.0.0.1,port 53105, socket 4
.....................
root@hdp3:/media/sf_workspace/sangerhoo/unp# ............/pollserver:4 bytes from 4 :dfd


..../pollserver:4 bytes from 4 :fdf


...../pollserver:10 bytes from 4 :sangerhoo


..../pollserver:6 bytes from 4 :sd


......../pollserver:6 bytes from 4 :hello

-------------------client----------------------

dfd
dfd


fdf
fdf


sangerhoo
sangerhoo


sd^H^H^H
sd


hello
hello




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