3 files changed, 26 insertions, 0 deletions
diff --git a/lib/ffi/function.rb b/lib/ffi/function.rb
index 6fff6ae..b4469be 100644
--- a/lib/ffi/function.rb
+++ b/lib/ffi/function.rb
@@ -32,10 +32,20 @@ module FFI
   class Function
     # Only MRI allows function type queries
     if private_method_defined?(:type)
+      # Retrieve the return type of the function
+      #
+      # This method returns FFI type returned by the function.
+      #
+      # @return [FFI::Type]
       def return_type
         type.return_type
       end
 
+      # Retrieve Array of parameter types
+      #
+      # This method returns an Array of FFI types accepted as function parameters.
+      #
+      # @return [Array<FFI::Type>]
       def param_types
         type.param_types
       end
diff --git a/lib/ffi/library.rb b/lib/ffi/library.rb
index 8af457d..9394902 100644
--- a/lib/ffi/library.rb
+++ b/lib/ffi/library.rb
@@ -542,10 +542,21 @@ module FFI
       end || FFI.find_type(t)
     end
 
+    # Retrieve all attached functions and their function signature
+    #
+    # This method returns a Hash of method names of attached functions connected by #attach_function and the corresponding function type.
+    # The function type responds to #return_type and #param_types which return the FFI types of the function signature.
+    #
+    # @return [Hash< Symbol => [FFI::Function, FFI::VariadicInvoker] >]
     def attached_functions
       @ffi_functions || {}
     end
 
+    # Retrieve all attached variables and their type
+    #
+    # This method returns a Hash of variable names and the corresponding type or variables connected by #attach_variable .
+    #
+    # @return [Hash< Symbol => ffi_type >]
     def attached_variables
       (
         (@ffi_gsvars || {}).map do |name, gvar|
diff --git a/lib/ffi/variadic.rb b/lib/ffi/variadic.rb
index 246b52f..389c53c 100644
--- a/lib/ffi/variadic.rb
+++ b/lib/ffi/variadic.rb
@@ -67,6 +67,11 @@ module FFI
       invoker
     end
 
+    # Retrieve Array of parameter types
+    #
+    # This method returns an Array of FFI types accepted as function parameters.
+    #
+    # @return [Array<FFI::Type>]
     def param_types
       [*@fixed, Type::Builtin::VARARGS]
     end