hacintosh hacintosh - 1 month ago 16
Ruby Question

Iterate over Ruby FFI Struct layout

I am using the really awesome ruby ffi library to access functions in a c library in ruby.

Is there a way to iterate over the layout of a Ruby FFI::Struct?

example FFI::Struct:

class Example < FFI::Struct
layout :name, string,
:desc, :string,
:type, :int,
:value, :string
end


this doesn't seem to work but something like the below pseudo code:

example_struct.each_key do |key|
puts key
end

Answer

Looking at the source for struct.rb, I found that you can call Struct::members to get an array of the symbols you've defined as "keys".

From there, you've also got Struct::values for the values of each member, Struct::offsets for the offsets of each member, and a few other methods.