//---------------------------------------------------------
// com.mq.cc
//---------------------------------------------------------

#include "check.h"

#include <cstring>
#include <iostream>
#include <mqueue.h>
#include <sys/wait.h>
#include <unistd.h>

//---------------------------------------------------------

int main()
{
    const unsigned N = 64;
    const char EOS = '\0', *EOM = &EOS;

    mqd_t id = 0;
    char file[] = "/mq", msg[N];
    struct mq_attr attr = {
        0, 1, 1, 0}; // {flags, maxmsg, msgsize, curmsgs}

    if (check(fork())) // parent/reader
    {
        id = check(mq_open(file, O_CREAT | O_RDONLY, 0600, &attr));
        std::cout << "parent/reader: ";
        do
        {
            check(mq_receive(id, msg, N, NULL));
            std::cout << msg[0];
        } while (msg[0] != EOS); // ¿fin de mensaje?
        wait(nullptr);
    }
    else // child/writer
    {
        id = check(mq_open(file, O_CREAT | O_WRONLY, 0600, &attr));
        std::cout << " child/writer: ";
        for (char c = 'a'; c <= 'z'; ++c)
        {
            check(mq_send(id, &c, 1, 0));
            std::cout << c;
        }
        check(mq_send(id, EOM, 1, 0)); // fin de mensaje
    }

    std::cout << std::endl;
    mq_close(id);
}

//---------------------------------------------------------