Why use FFI
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Why should you write your next Ruby extension using ruby-ffi? Why should you consider re-implementing an existing standard extension using ruby-ffi? The section below aims to give you some good answers to these questions.
An FFI extension doesn't need compilation
You don't need a compiler installed on your system to be able to run FFI extensions. Nor do you need to install the development versions of libraries; the runtime versions will do. The libraries you link against will need to have been compiled at some point, of course, but odds are you won't have had to do it.
An FFI extension is multi-platform and multi-implementation
An FFI extension works without changes on Ruby, JRuby, and any other Ruby VM that supports FFI.
An FFI extension is easy to read
Because all the code for an FFI extension is written in Ruby, it's as easy to read as any other Ruby code. There is no need to switch mental modes from C programming to Ruby programming.
An FFI extension is easy to write
Writing a Ruby-FFI based extension is easy thanks to an intuitive DSL. For example, the snippet below is all you need to interface with the 'puts' function defined in the libc C library:
module Foo extend FFI::Library ffi_lib FFI::Library::LIBC attach_function :puts, [ :string ], :int end
See Basic Usage for other examples.
An FFI extension is easy to maintain
Because an FFI extension is easy to read and to write, it is also easy to maintain.
An FFI extension is impervious to changes in the internal Ruby API
An FFI extension isn't broken by changes to the internal Ruby extension API.