If the function returns (LtMeshingCallBacks)NULL, a memory allocation error has occurred.

Once a meshing callbacks data structure has been created, the API user can manipulate the callbacks which it represents, and attach the whole thing to a meshing refinement, so that the callbacks can be utilised inside the triangulation code.

/*
 * Create a brand new meshing callbacks
 */
mesh_calls = LiMeshingCallBacksCreate();
data = LiDataCreate();
if ( mesh_calls && data )
{
   LiDataSetGenericPtr(data, (LtGenericPtr)mesh_calls);
   status = 
      LiMeshingRefinementSetCriterion(meshref,
                                      LI_MESH_CRIT_CALLBACKS,
                                      data);
   ...
}