load dynamic libraries, bind functions from within ruby code

 Ruby-FFI is a ruby extension for programmatically loading dynamic
 libraries, binding functions within them, and calling those functions
 from Ruby code. Moreover, a Ruby-FFI extension works without changes
 on Ruby and JRuby. Discover why should you write your next extension
 using Ruby-FFI at https://github.com/ffi/ffi/wiki/Why-use-FFI.