消息队列实现聊天室功能

头文件

 

#ifndef __msg__
#define __msg__
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/msg.h>
#include <sys/ipc.h>
#include <unistd.h>
#include <sys/types.h>
#include <pthread.h>
#include <sys/stat.h>

struct msg_tmp
{
    int type;
    char name[10];
    char msg[40];
};
typedef struct msgbuf
{
    long mtype;
    struct msg_tmp m_data;    
}MSG; 

extern int type;
extern pthread_t th_snd,th_rcv; 
extern char master_name[10];  //用户名
extern MSG data_snd,data_rcv;  //接受数据结构 发送数据结构
extern pthread_mutex_t mutex;   //互斥锁
extern int msg_id;

extern int get_msg_id(void);
extern void *msg_snd(void *arg);    //发送信息
extern void *msg_rcv(void *arg);    //接受信息

#endif


子函数

 

#include "my_type.h"
// get type

/*   获得消息队列描述，如果是首次加入信息队列，则等待下一个节点加入，并记录其节点号 */
int get_msg_id(void)
{
    int id_tmp;
    int status=0;
    MSG    tmp;
    key_t key;
    if( (key=ftok(".",0xff))==-1 )  //
    {
        perror("ftok error");
        exit(1);
    }
    if( (id_tmp=msgget(key,IPC_CREAT|0666))==-1 ) //创建消息队列
    {
        perror("msgget error");
        exit(1);
    }
    else
    {
        printf("id_tmp = %d \n",id_tmp);
        if(msgrcv(id_tmp,&tmp,sizeof(MSG),10,IPC_NOWAIT)==-1)//获取消息队列信息，该信息存储在节点号为10的节点，tmp.m_data.type 为消息队列中总的节点数
        {
            type=1;
            tmp.mtype=10;
            tmp.m_data.type=type;
            msgsnd(id_tmp,&tmp,sizeof(MSG),0);//获得总节点数后在存储10号节点
            printf("wait in: \n");
            while( (pthread_mutex_lock(&mutex)) && ( msgrcv(id_tmp,&tmp,sizeof(MSG),10,0)!=-1 ) && ( tmp.m_data.type==1 ) )
            { //如果只有一个节点，则等待第二个节点加入
                msgsnd(id_tmp,&tmp,sizeof(MSG),0);
                pthread_mutex_unlock(&mutex); 
                usleep(50);
                status=1;
            }
            if(status==1)//在while中，有一次加锁，while退出时，缺少一次解锁
                pthread_mutex_unlock(&mutex);
                
            printf("wait out : \n");
        }
        else
        {
            type=tmp.m_data.type+1;//获得总结点数，则自己节点号为总结点数加1，更新总结点数
            tmp.m_data.type=type;
            tmp.mtype=10;
            pthread_mutex_lock(&mutex);
            msgsnd(id_tmp,&tmp,sizeof(MSG),0);            
            pthread_mutex_unlock(&mutex);
        }
    }
    return id_tmp;
}
// msg send

void *msg_rcv(void *arg)
{    
    MSG tmp;
    int nail;
    data_snd.mtype=type;
    sleep(1);
    printf("type = %d \n",type);
    while(1)  //首节点，接受尾节点信息，判断是否为自己信息，否则输出，同时写入自己节点号，是则忽略。
    {
        pthread_mutex_lock(&mutex);
        msgrcv(msg_id,&tmp,sizeof(MSG),10,IPC_NOWAIT);
        nail=tmp.m_data.type;
        printf("nail:%d type: %d ",nail,type);
        msgsnd(msg_id,&tmp,sizeof(MSG),0);
        pthread_mutex_unlock(&mutex);
        if(type==1)
        {
            puts("type1 in \n");
            data_rcv.mtype=tmp.m_data.type;
            msgrcv(msg_id,&data_rcv,sizeof(MSG),nail,0);        
            puts("type1 out \n");
        }
        else //各节点操作流程为:读取前一个节点信息，判断是否自己发送，否，则输出显示，同时写入自己的节点处，是则忽略本次。信息呈环状流动，流动一圈后，停止。
        {
            msgrcv(msg_id,&data_rcv,sizeof(MSG),type-1,0);        
        }
        if(data_rcv.m_data.type!=type)
        {
            printf("[%s] : %s \n",data_rcv.m_data.name,data_rcv.m_data.msg);
            data_rcv.mtype=type;
            msgsnd(msg_id,&data_rcv,sizeof(MSG),0);
        }
    //    pthread_mutex_lock(&mutex);

    //    pthread_mutex_unlock(&mutex);

    }
    pthread_exit(0);
}
//msg receive

void *msg_snd(void *arg)
{
//    sleep(1);

//    pthread_mutex_lock(&mutex);
//发送数据
    while(1)
    {
    //    pthread_mutex_lock(&mutex);

        data_snd.mtype=type;
        data_snd.m_data.type=type;
        strcpy(data_snd.m_data.name,master_name);
        printf("%s say: ",master_name);
        scanf("%s",data_snd.m_data.msg);
        msgsnd(msg_id,&data_snd,sizeof(MSG),0);
    //    pthread_mutex_unlock(&mutex);

    //    pthread_mutex_unlock(&mutex);

    }
    pthread_exit(0);
}



 

main函数

 

#include "my_type.h"

MSG data_snd,data_rcv;
char master_name[10];
int type=0;
pthread_mutex_t mutex;
pthread_t th_snd,th_rcv;
int msg_id;
int main(void)
{
    pthread_mutex_init(&mutex,NULL);
    puts("init mutex ok \n");
    msg_id=get_msg_id(); //get msg_id

    printf("msg_id = %d\n",msg_id);
    printf("input your nickname:\n");
    scanf("%s",master_name);
    pthread_create(&th_snd,NULL,msg_snd,NULL); //创建子线程
    pthread_create(&th_rcv,NULL,msg_rcv,NULL);
    pthread_join(th_snd,NULL);
    pthread_join(th_rcv,NULL);  //等待结束信号
    return 0;
}