Create and insert data in mq_queue Posix. Tested in Linux (OpenSUSE Tumbleweed) and Solaris 5.11.

posix_mq_send_CMakeLists.txt

cmake_minimum_required(VERSION 3.9)
project(posix_mq_send)

set(CMAKE_CXX_STANDARD 98)
set(GCC_COVERATE_LINK_FLAGS "-lrt")
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${GCC_COVERATE_LINK_FLAGS}")

add_executable(posix_mq_send main.cpp)

posix_mq_send_main.cpp

#include <iostream>
#include <cstdlib>
#include <mqueue.h>
#include <errno.h>
#include <cstring>

#ifdef sun
#include <fcntl.h>
#endif

using namespace std;

int main(int argc, char **argv) {
    cout << "Message Posix Sample" << endl;

    if (argc < 2) {
        cerr << "Usage: " << endl
             << "\t" << argv[0] << " <data>" << endl
             << "\tWhere <data> is text for send to queue" << endl;
        return EXIT_FAILURE;
    }

    mqd_t queue;

    queue = mq_open("/mq_test", O_CREAT|O_WRONLY, S_IRUSR|S_IWUSR, NULL);
    if (queue == static_cast<mqd_t>(-1)) {
        cerr << "Error on open queue mq_test: "
             << strerror(errno)
             << endl;
        return EXIT_FAILURE;
    }

    if (mq_send(queue, argv[1], strlen(argv[1]), 0) == -1) {
        cerr << "Error on send data to queue: "
             << strerror(errno)
             << endl;
        return EXIT_FAILURE;
    }

    cout << "Message opened success" << endl;
    cout << "Message inserted in queue" << endl;

    if (mq_close(queue) == -1) {
        cerr << "Error on close queue: "
             << strerror(errno)
             << endl;
        return EXIT_FAILURE;
    }

    cout << "Message close success" << endl;

    return EXIT_SUCCESS;
}