joystick object
This function checks if a particular button on the joystick is currently up.
bool button_up(int button)
Parameters:
button
The ID of a joystick button to check (see remarks).
Return value:
true if the button is up, false if it is not or if an error occurs.
Remarks:
The difference between button_up and button_released is that button_released will only return true when the user first releases the button, while button_up will continue returning true until the button is pushed down again.
The joystick object supports up to 128 buttons, ranging from 0 to 127. However the actual maximum button is determined by the buttons property for the given device, meaning that the allowed range is from 0 to buttons minus 1.
It is important to remember when mapping functions to joystick buttons that devices can vary greatly between models, supporting anything between 3 and 15 buttons, and therefore it is always a good idea to map the most common activities to buttons with lower numbers.
Example:

    // The engine sound will only play when button 0 is down.

    void main()
    {
    show_game_window("Joystick buttons");
    sound truck;
    joystick stick;
    if(stick.joysticks==0)
    {
    alert("Error", "No joysticks seem to be attached.");
    exit();
    }
    truck.load("engine.wav");
    while(key_up(KEY_ESCAPE))
    {
    if((stick.button_up(0))&&(truck.playing))
    truck.pause();
    else
    truck.play_looped();
    wait(5);
    }
    }