/*********************************************************************************
 *      Copyright:  (C) 2025 LingYun IoT System Studio
 *                  All rights reserved.
 *
 *       Filename:  mq_recv.c
 *    Description:  This file is Message Queue(receiver) example program.
 *
 *        Version:  1.0.0(11/10/2025)
 *         Author:  Guo Wenxue <guowenxue@gmail.com>
 *      ChangeLog:  1, Release initial version on "11/10/2025 10:06:53 AM"
 *
 ********************************************************************************/
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>

#define FTOK_PATH           "/dev/zero"
#define FTOK_PROJID         0x22

typedef struct msg_s
{
    long  mtype;
    char  mtext[512];
} msg_t;

int main(int argc, char **argv)
{
    key_t             key;
    msg_t             msg;
    int               msgid;
    int               msgtype=2;
    int               i;

    if( (key=ftok(FTOK_PATH, FTOK_PROJID)) < 0 )
    {
        printf("ftok() get IPC token failure: %s\n", strerror(errno));
        return -1;
    }

    msgid = msgget(key, IPC_CREAT|0666);
    if( msgid < 0)
    {
        printf("shmget() create shared memroy failure: %s\n", strerror(errno));
        return -2;
    }
    printf("key[%d] msgid[%d] msgypte[%d]\n", (int)key, msgid, msgtype);

    printf("Waiting for messages...\n");
    while(1)
    {
        memset(&msg,0,sizeof(msg));
        if( msgrcv(msgid, &msg, sizeof(msg.mtext), msgtype, 0) < 0 )
        {
            printf("msgsnd() receive message failure: %s\n", strerror(errno));
            break;
        }

        printf("Received: %s", msg.mtext);
        if (strncasecmp(msg.mtext, "exit", 4) == 0)
            break;
    }

    msgctl(msgid, IPC_RMID, NULL);
    return 0;
}