How to run an infinite loop in real time - Linux?

I wrote a hello world program with an infinite loop with Xenomai API, as follows: This gets terminated soon.

I actually wanted to test this program's real time latency through latencytop.
How to run an infinite loop in real time?

RT_TASK demo_task;

void demo(void *arg)
{
    RT_TASK *curtask;
    RT_TASK_INFO curtaskinfo;

    curtask=rt_task_self();
    rt_task_inquire(curtask,&curtaskinfo);

    printf("Task name : %s \n", curtaskinfo.name);

        //------------------ hello world --------------------
    while (1)
    {
        printf("Hello World!\n");
    }

}

int main(int argc, char* argv[])
{
    char  str[10];

    rt_print_auto_init(1);

    mlockall(MCL_CURRENT|MCL_FUTURE);

    printf("start task\n");

    sprintf(str,"hello");
    rt_task_create(&demo_task, str, 0, 50, 0);

    rt_task_start(&demo_task, &demo, 0);
}

At the bottom of main, also put an infinite loop. while(1) sleep(10000) is usually good on full-blown linux, don't know about RT-world.

What's happening is that you're spawning off a new task and then main is immediately returning after this, which exits the entire process.