module FFI
  type ffi_type = Type | Symbol
  type ffi_auto_type = ffi_type | DataConverter[untyped, untyped, untyped]
  type type_map = Hash[Symbol | DataConverter[untyped, untyped, untyped], Type]

  class CallbackInfo = FunctionType
  class FunctionInfo = FunctionType
  class NativeLibrary = DynamicLibrary

  VERSION: String
  TypeDefs: type_map

  type current_process = Object
  CURRENT_PROCESS: current_process
  USE_THIS_PROCESS_AS_LIBRARY: current_process

  class NotFoundError < LoadError
  end

  private def self.custom_typedefs: () -> type_map
  def self.errno: () -> Integer
  def self.errno=: (Integer) -> Integer
  def self.find_type: (ffi_auto_type name, ?type_map? type_map) -> Type
  def self.make_shareable: [T] (T obj) -> T
  def self.map_library_name: (_ToS lib) -> String
  def self.type_size: (ffi_auto_type type) -> Integer
  def self.typedef: (ffi_auto_type old, Symbol add) -> Type
  alias self.add_typedef self.typedef
end
