Find the control surface associated with a given action
PtSurface_t *PtFindSurfaceByAction( PtWidget_t *widget, PtWidgetClassRef_t const *cref, unsigned short action_id, PtSurface_t const *surface );
This function locates a control surface using its associated action as a search key.
The widget argument specifies the widget to search, while cref and action_id specify the class and manifest of the action to seek. The surface argument specifies the surface at which to start the search, letting you find all the surfaces in a widget associated with a particular action. If this argument is NULL, the search begins at the first surface within the widget.
|This function ignores regular surfaces (i.e. those created using PtCreateSurface() as opposed to PtCreateActionSurface()).|
A pointer to the structure representing the control surface, or NULL if no more surfaces associated with the specified action could be found.
|Since control surfaces are maintained internally as an array, it's not uncommon for them to shift around in memory as surfaces are added and removed, thereby possibly invalidating a pointer returned by this function. As such, all surface pointers should be regarded as transient, and you should retrieve an updated copy whenever there's a chance that the widget's surface configuration might have changed.|
Control Surfaces chapter of the Photon Programmer's Guide