Thread: Unable to join MQ

I am using SysV for sending/receiving messages.

Inside the thread function of my Server class is where I create the key and MQ. I have tested that this is done successfully and the mqID of the new MQ is stored in the variable mtext in a struct msgbuf.

Code:

struct msgbuf {    
long mtype;    
char mtext[100]; 
};

This is how I create the mqID in the thread function of the server class:

Code:

void*thread_function(void*arg){
      int temp;//temp placement for current client
      temp=i;   
      key_t keyT;    
      struct msgbuf bufT;   
      keyT=ftok("mcs1.c", 'B'); //create key for client[temp]  
      if ((client[temp].mqID=msgget(keyT, 0666 | IPC_CREAT))==-1){       perror("msgget");    }   
      bufT.mtype=2;   //1. SET MTYPE TO 2    
      sprintf(bufT.mtext, "%d\n", client[temp].mqID);//2. SET MTEXT TO MQID OF PRIVATE MQ   
      if (msgsnd(msqid, &bufT, sizeof(bufT.mtext),0)==-1)              {perror("msgsnd");} //3. SEND TO CLIENT using global MQ   
 ... 
}

So the MQID of the new MQ i just created is stored in bufT, which is then sent as a message to a client class through the global MQ created in the Servers main ( I will post the code if it will help)

This is how the Client class receives the message from the server, takes the MQID and attempts to join the MQ:

Code:

...

Code:

if(msgrcv(msqid, &buf, sizeof(buf.mtext), 2, 0) == -1){ //RECEIVE ACK MSG            
    perror("msgrcv");   
}   
else{            
    printf("ack received\n");    
}   
key_t key1;    
key1=atoi(buf.mtext);    
if ((mqT=msgget(key1, 0666)) == -1){            
    printf("UNABLE TO JOIN PRIVATE MQ");     
    perror("msgget");                    
    printf("%d", key1);    
} 
...

Whenever I run the server and then a client, it says msgget: No such file or directory on the terminal running the client program. Even though when I print the key in the client class and is the correct key, it still can't join the MQ. What is the reason for this?

Originally Posted by Codeplug

You are treating "buf.mtext" as a "key" - but server is sending the q-id, not the key.

gg

gg indeed, totally missed that. No one on stackoverflow got it either