In Ruby API, developer can get imported classifications by name or index
# Get schema by name: schema = Sketchup.active_model.classifications["IFC 2x3"] # Get schema by index: schema = Sketchup.active_model.classifications
But similar method is missing in C API. Class Classifications provides very limited function. It must requires name as param, and there is no other way to get the names of imported classification in model. Current API is nearly unusable.
SU_RESULT SUClassificationsGetSchema( SUClassificationsRef classifications, const char * schema_name, SUSchemaRef * schema_ref)
C API of classifications should be added with get num and list methods.