C++ 中消息队列函数实例详解

C++ 中消息队列函数实例详解

1.消息队列结构体的定义

typedef struct{
    uid_t  uid;  
    gid_t  gid;  
    udi_t  cuid;  
    gid_t  cgid;  
    mode_t mode;  
    ulong_t seq;  
}ipc_perm;

typedef stuct{
    struct ipc_perm msg_perm;   
    struct msg   *msg_first;   
    struct msg   *msg_last;   
    msglen_t     msg_cbytes;   
    msgqnum_t    msg_qnum;    
    msglen_t    msg_qbytes;   
    pid_t msg_lspid;   
    pid_t msg_lrpid;   
    time_tmsg_stime;   
    time_tmsg_rtime;   
    time_tmsg_ctime;   
}msqid_ds;

typedef struct
{
    long mtype;
    char mbuf[MSGLEN];
}Message;

2.创建消息队列：

   
#include
#include
#include

int MsgGet(int key)
{
    int ret;
    ret=msgget(key,0600|IPC_CREAT);
//   ret=msgget(key,0600|IPC_CREAT|IPC_EXCL);
    if(ret<0)
 perror("creat msgid error");
    printf("msgid=%d/n",ret);
    system("ipcs -q -i ret");
    return ret;
}
int main(int argc,char *agrv[])
{
    int key;
    printf("pleasse input msgkey:");
    scanf("%d",&key);
    MsgGet(key);
    return 0;
}

3.向消息队列中发送消息msgsnd

#include "typemsg.h"
int MsgSnd(int msqid,char *buf,int len,int flag)
{
    int ret;
    ret=msgsnd(msqid,buf,len,flag);
    if(ret<0)
 perror("msgsnd error");
    system("ipcs -q");
    return ret;
}

int main()
{
    int msqid,len,stype;
    Message msgb;
    memset(&msgb,0,sizeof(Message));
    printf("msgsnd:please input msqid:");
    scanf("%d",&msqid);
    printf("please input msgtype:");
    scanf("%d",&stype);
    msgb.mtype=stype;
    strcpy(msgb.mbuf,"zhangweia");
    MsgSnd(msqid,(char *)&msgb,sizeof(Message),0);
    return 0;
}

4.从队列中获取消息 msgrcv

#include "typemsg.h"
int MsgRcv(int msqid,char *buf,int msglen,long type,int flag)
{
    int ret;
    ret=msgrcv(msqid,buf,msglen,type,flag);
    if(ret<0)
    perror("msgrcv error");
    system("ipcs -q");
    return ret;

}

int main()
{
    int msqid,len;
    long ttype;
    Message mbuf;
    printf("msgrcv:please input recv msqid:");
    scanf("%d",&msqid);
    MsgRcv(msqid,(char *)&mbuf,8900,0,IPC_NOWAIT);
    printf("recv message=%s/n",mbuf.mbuf);
    Put_String((unsigned char *)&mbuf,sizeof(Message));
    return 0;
}

6.消息队列的控制msgctl

#include "typemsg.h"
int MsgCtl(int msqid,int cmd,struct msqid_ds *buff)
{
    int ret;
    ret=msgctl(msqid,cmd,buff);
    if(ret<0)
    {
 perror("msgctl error");
 return -1;
    }
    return 0;
}

int main()
{
    int msqid,type;
    struct msqid_ds info;
    printf("please input msqid /nand type(1:icp_rmid;2:ipc_stat)");
    scanf("%d%d",&msqid,&type);
    if(type==1)
    {
 MsgCtl(msqid,IPC_RMID,NULL);
 printf("delete queue success:%d/n",msqid);
    }else if(type==2)
    {
 MsgCtl(msqid,IPC_STAT,&info);
 printf("get queue stat:%d/n",msqid);
    }
    return 0;

}

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