User`s guide

3 Writing S-Functions As C-MEX files
3-98
ssGetParentSS(S)
This is typically not used in S-functions. It returns the parent
SimStruct or NULL if the S is the root SimStruct.
ssGetRootSS(s)
This is typically not used in S-functions. It returns the root
SimStruct of the tree of SimStruct’s.
ssSetPlacementGroup
(S,groupName)
This is an advanced feature typically used for Real-Time Workshop
device driver blocks. It is provided for S-functions that are either
sources (i.e., no input ports) or sinks (i.e., no output ports).
S-functions which share the same placement group name string
will be placed adjacent to each other in block execution (i.e., the
sorted list). The placement group should be set in
mdlInitializeSizes.
Table 3-5: General SimStruct Macros (Continued)
Macro Description