mq1_a.c

/*******************************************
* Author     : Diego Cordoba / @d1cor      *
* Contact    : juncotic.com / um.edu.ar    *
*******************************************/

#include<stdio.h>
#include<stdlib.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<unistd.h>
#include<string.h>
#include<fcntl.h>
#include<errno.h>
#include<sys/ipc.h>
#include<sys/msg.h>
#include<mqueue.h>
#define MSG_SIZE 128

#define SERVER_QUEUE_NAME   "/test"
#define QUEUE_PERMISSIONS 0660
#define MAX_MESSAGES 10
#define MAX_MSG_SIZE 256
#define MSG_BUFFER_SIZE MAX_MSG_SIZE + 10



int main(int argc, char** argv) {

    char *error;

    mqd_t msg_id;

    struct mq_attr attr;
    mq_unlink(SERVER_QUEUE_NAME);

    attr.mq_flags = 0;
    attr.mq_maxmsg = MAX_MESSAGES;
    attr.mq_msgsize = MAX_MSG_SIZE;
    attr.mq_curmsgs = 0;

    if ((msg_id = mq_open (SERVER_QUEUE_NAME, O_RDONLY | O_CREAT, QUEUE_PERMISSIONS, &attr)) == -1) {
        perror ("Server: mq_open (server)");
        exit (1);
    }

    char buffer [MSG_BUFFER_SIZE];

    while (mq_receive (msg_id, buffer, MSG_BUFFER_SIZE, NULL)) {
        printf("Server message received: %s\n", buffer);
        memset(buffer, 0, MSG_BUFFER_SIZE);
    }


    mq_unlink(SERVER_QUEUE_NAME);


    return 0;

err:
    fprintf(stderr,"ERROR %s (%d) - %s\n",error,errno,strerror(errno));
    exit(errno);
}

//  https://tmate.io/t/ro-pBYOPTf8HfhYVxmXEFGuTR8B1