Linux Message Queue Question!!!

Discussion in 'C Programming' started by Shao Tian, Jul 28, 2010.

  1. Shao Tian

    Shao Tian

    Joined:
    Jul 28, 2010
    Messages:
    2
    #include <stdio.h>
    #include <stdlib.h>
    #include <linux/ipc.h>
    #include <linux/msg.h>
    #include <sys/types.h>
    #include <wait.h>
    #include <unistd.h>
    #include <errno.h>
    typedef struct
    {
    long mtype;
    int veh_type;//1: car, 2: truck
    int pid; //msg id
    } msg;
    main()
    { msg message;
    message.mtype=1;
    message.veh_type=0;
    message.pid=0;

    int qid=msgget(111,IPC_CREAT|0666);
    msgsnd(qid,&message,sizeof(msg),0);

    struct msqid_ds buf;

    msgctl(qid,IPC_STAT,&buf);
    int result=buf.msg_qbytes;
    printf("%d\n",result);
    msgctl(qid,IPC_RMID,0);
    }


    Hi every body:
    I am facing a wired problem when I trying to figure out how message queue works

    In the code above I simply want to send a message to an message queue. and output the number of messages in the queue. But the output is 0.....

    Is there any one knows how to solve it...
    Thanks very much!!! :D
     
    Shao Tian, Jul 28, 2010
    #1
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