SimStruct representing an S-Function block or a Simulink® model.
The SimStruct at the root of the SimStruct hierarchy.
Use to obtain the root of the SimStruct hierarchy
containing S. If S is, itself,
the root SimStruct then ssGetRootSS returns S.
There is one SimStruct for each S-function
in your model and one for the model itself. The structures are arranged
as a tree with the model SimStruct as the root.
This macro is for internal use. User-written S-functions should not
use the ssGetRootSS macro.