client.c

提供了非阻塞的客户端和服务器端通信的实例程序。用linux下的C语言实现。

#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/socket.h>
#include <resolv.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/types.h>

#define MAXBUF 1024

int main(int argc, char **argv)
{
    	int sockfd, len;
    	struct sockaddr_in dest;
    	char buf[MAXBUF + 1];
    	fd_set rfds;
    	struct timeval tv;
	int retval, maxfd = -1;

	if (argc != 3) {
        	printf("Usage: %s IP Port",argv[0]);
        	exit(0);
    	}

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

	bzero(&dest, sizeof(dest));
    	dest.sin_family = AF_INET;
    	dest.sin_port = htons(atoi(argv[2]));
    	if (inet_aton(argv[1], (struct in_addr *) &dest.sin_addr.s_addr) == 0) {
        	perror(argv[1]);
        	exit(errno);
    	}

	if(connect(sockfd, (struct sockaddr *) &dest, sizeof(dest)) != 0) {
        	perror("Connect ");
        	exit(errno);
    	}

	printf("connect to server...\n");		
	while (1) 
	{

                	FD_ZERO(&rfds);           
            		FD_SET(0, &rfds);
            		maxfd = 0;
            
            		FD_SET(sockfd, &rfds);
            		if (sockfd > maxfd)
                		maxfd = sockfd;
            
            		tv.tv_sec = 1;
            		tv.tv_usec = 0;
          
            		retval = select(maxfd + 1, &rfds, NULL, NULL, &tv);

			if (retval == -1) 
			{
		                printf("select error! %s", strerror(errno));              
				break;
		        } else if (retval == 0) {
             			//printf("no msg,no key, and continue to wait……\n"); 
                		continue;
            		} else {
				if (FD_ISSET(0, &rfds)) 
				{                
                    			bzero(buf, MAXBUF + 1);
                    			fgets(buf, MAXBUF, stdin);				
                    			if (!strncasecmp(buf, "quit", 4)) 
					{
                        			printf("request terminal chat！\n");
                        			break;
                    			}
                    			len = send(sockfd, buf, strlen(buf) - 1, 0);
                    			if (len > 0)
                        			printf("msg:%s send successful，totalbytes: %d！\n", buf, len);
                    			else {
                        			printf("msg:'%s  failed!\n", buf);
                        			break;
                    			}
                		}
                		else if (FD_ISSET(sockfd, &rfds)) 
				{ 
                    			bzero(buf, MAXBUF + 1);
                    			len = recv(sockfd, buf, MAXBUF, 0);
                    			if (len > 0)
                        			printf("recv:'%s, total: %d \n", buf, len);
                    			else  
					{
						if (len < 0) 
	                            			printf("recv failed！errno:%d，error msg: '%s'\n", errno, strerror(errno));
	                        		else
	                            			printf("other exit，terminal chat\n");
	                        		break;
					}
                    		}				
			}
	}

	close(sockfd);
	return 0;
}