redhat man page for sdl_joystickgetball

SDL_JoystickGetBall(3)						 SDL API Reference					    SDL_JoystickGetBall(3)

NAME
       SDL_JoystickGetBall- Get relative trackball motion

SYNOPSIS
       #include "SDL.h"

       int SDL_JoystickGetBall(SDL_Joystick *joystick, int ball, int *dx, int *dy);

DESCRIPTION
       Get the ball axis change.

       Trackballs can only return relative motion since the last call to SDL_JoystickGetBall, these motion deltas a placed into dx and dy.

RETURN VALUE
       Returns 0 on success or -1 on failure

EXAMPLES
       int delta_x, delta_y;
       SDL_Joystick *joy;
       .
       .
       .
       SDL_JoystickUpdate();
       if(SDL_JoystickGetBall(joy, 0, &delta_x, &delta_y)==-1)
	 printf("TrackBall Read Error!
       ");
       printf("Trackball Delta- X:%d, Y:%d
       ", delta_x, delta_y);

SEE ALSO
       SDL_JoystickNumBalls

SDL
							      Tue 11 Sep 2001, 23:00					    SDL_JoystickGetBall(3)