The 'libffi' library provides a portable, high level programming interface to
various calling conventions. This allows a programmer to call any function
specified by a call interface description at run time.

FFI stands for Foreign Function Interface. A foreign function interface is the
popular name for the interface that allows code written in one language to call
code written in another language. The 'libffi' library really only provides the
lowest, machine dependent layer of a fully featured foreign function interface.
A layer must exist above 'libffi' that handles type conversions for values
passed between the two languages.