I recently discovered Crobot which is (briefly) a game where each player codes a virtual robot in a pseudo-C language. Each robot is then put in an arena where it fights against other robots.

A robots' source code has this shape :

/* Beginning file robot.r */
main()
{
    while (1)
    {
        /* Do whatever you want */
        ...
        move();
        ...
        fire();
    }
}
/* End file robot.r */

You can see that :

1. The code is totally independent from any library/include
2. Some predefined functions are available (move, fire, etc…)
3. The program has its own game loop, and consequently is not called every frame

My question is roughly : how does it work ?

It seems that each robot's code is compiled by the main program and then used in a way I cannot understand. I thought it could yields a thread for each robot, but I have not any proof of this and it seems a bit complicated to achieve it. Any idea how it could work, someone ?