Complex sentence: The aim is to achieve this connection with minimal effort: a small number of directives are added to the program's header files, and then the SWIG tool creates source code which provides the glue between C/C++ and the target language.
Split into simpler sentences: The aim is to achieve this connection with minimal effort: a small number of directives are added to the program's header files. Running the SWIG tool creates source code which provides the glue between C/C++ and the target language.