Calling a library by function gives you access to common user libraries that have been installed using the SL System command.
To call a Library using By Function, perform the following:
Create an External class in the model named library.
Set the By Function class configuration property to True so that all external calls to the named library are By Function.
Set the Library Name class configuration property library.
There is no LDL+ invocation as ByFunction worked as a declarative affecting all calls to that library where it exists within the code.