====== (This is the legacy documentation for stable SDL2, the current stable version; [https://wiki.libsdl.org/SDL3/ SDL3] is the current development version.) ======
= SDL_JoystickGetBall =

Get the ball axis change since the last poll.

== Syntax ==

<syntaxhighlight lang='c'>
int SDL_JoystickGetBall(SDL_Joystick *joystick,
                        int ball, int *dx, int *dy);
</syntaxhighlight>

== Function Parameters ==

{|
|'''joystick'''
|the [[SDL_Joystick]] to query
|-
|'''ball'''
|the ball index to query; ball indices start at index 0
|-
|'''dx'''
|stores the difference in the x axis position since the last poll
|-
|'''dy'''
|stores the difference in the y axis position since the last poll
|}

== Return Value ==

Returns 0 on success or a negative error code on failure; call
[[SDL_GetError]]() for more information.

== Remarks ==

Trackballs can only return relative motion since the last call to
[[SDL_JoystickGetBall]](), these motion deltas are placed into
<code>dx</code> and <code>dy</code>.

Most joysticks do not have trackballs.

== Version ==

This function is available since SDL 2.0.0.

== Related Functions ==

:[[SDL_JoystickNumBalls]]

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[[CategoryAPI]]