一个小QQ程序源代码（LINUX系统）

#include<stdlib.h> #include<sys/types.h> #include<sys/socket.h> #include<netinet/in.h> #include<unistd.h> #include<pthread.h> #include<stdio.h> #include<string.h> #include<arpa/inet.h> #define PORT 8848 #define BACKLOG 1000 #define MAXDATASIZE 128 #define MAXUSER 9 int select_user(char uname); void process_cli(int connectfd,struct sockaddr_in client); void *creat_conn(void *arg) struct ARG { int connfd; struct sockaddr_in client; }; struct USER { int connfd; char name; }user[MAXUSER]; static int u_len=0; int main() { int listenfd,connectfd; pthread_t thread; struct ARG *arg; struct sockaddr_in server; struct sockaddr_in client; int sin_size; //create tcp socket printf("socket......"); if((listenfd=socket(AF_INET,SOCK_STREAM,O))==-1) { perror("creating socket failed."); exit(1); } int opt=SO_REUSEADDR; setsockopt(listenfd,SOL_SOCKET,SO_REUSEADDR,&opt,sizeof(opt)); bzero(&server,sizeof(server)); server.sin_family=AF_INET; server.sin_port=htons(PORT); server.sin_addr.s_addr=htonl(INADDR_ANY); printf("bind......"); if(bind(listenfd,(struct sockaddr *)&server,sizeof(struct sockaddr))==-1) { perror("bind error."); exit(1); } printf("listen......"); if(listen(listenfd,BACKLOG)==-1) { perror("lesten() error!"); exit(1); } sin_size=sizeof(struct sockaddr_in); sleep(1); while(1) { //accept() using main thread printf("accepting......\n"); if((connectfd=accept(listenfd,(struct sockaddr *)&client,(socklen_t *)&sin_size))==-1) { perror("accept() error!"); exit(1); } printf("cread pthread arg \n"); arg=malloc(sizeof (struct ARG)); arg->connfd=connectfd; memcpy((void *)&arg->client,&client,sizeof(client)); //invoke start_routine to handle this thread. if(pthread_create(&thread,NULL,creat_conn,(void *)arg)) { perror("pthread_creat() error!"); exit(1); } } close(listenfd); return 0; } void *creat_conn(void *arg) { int tid=pthread_self(); struct ARG *n_arg=arg; process_cli(n_arg->connfd,n_arg->client); } void process_cli(int connectfd,struct sockaddr_in client) { int num,ufd,i; int tid=pthread_self(); char recvbuf[MAXDATASIZE],sendbuf[MAXDATASIZE]; char cli_name[MAXDATASIZE]; char name; printf("IP:%s,\n",inet_ntoa(client,sin_addr)); //get client's name from client. user[u_len].connfd=connectfd; user[u_len].name='a'+u_len; printf("u_fd:%d,u_name:%c\n",user[u_len].connfd,user[u_len].name); if(u_len++>MAXUSER) u_len==0; while(1) { memset(recvbuf,0,MAXDATASIZE); num=recv(connectfd,recvbuf,MAXDATASIZE,0);//recv return the size. printf("num=%d\n",num); if(num<=0) { close(connectfd); perror("Client disconnected."); break; } printf("[%d]INFO:%s \n",tid,recvbuf); //choose the user. name=recvbuf[0]; //group send. if(name=='x') { for(i=0;i<=MAXUSER;i++) { if(user[i].connfd>0) { send(user[i].connfd,recvbuf,strlen(recvbuf),0); } } } //get user's socket fd ufd=select_user(name); if(ufd>0) { send(ufd,recvbuf,strlen(recvbuf),0); } } } int select_user(char uname) { int i; for(i=0;i<=MAXUSER;i++) { if(uname==user[i].name) return user[i].connfd; } return 0; }