require 'ffi'
require 'ffi/libc'

puts FFI::VERSION

class CPtr < FFI::AutoPointer
  def self.from_native(ptr, _ctx)
    raise Error, 'malloc failed' if ptr.null?
    super
  end

  def self.release(ptr)
    p ptr
    C.free(ptr) unless ptr.null?
  end
end

module C
  extend FFI::Library
  ffi_lib FFI::Library::LIBC

  attach_function :malloc, [:size_t], CPtr
  attach_function :free, [CPtr], :void
end

# ptr = FFI::AutoPointer.new(FFI::LibC.malloc(4), FFI::LibC.method(:free))
# p ptr
# p ptr.dup
# # 1.17.2
# # #<FFI::AutoPointer address=0x00005fa73349c690>
# # test_ffi.rb:28:in `initialize_copy': cannot duplicate unbounded memory area (RuntimeError)
# # 	from test_ffi.rb:28:in `initialize_dup'
# # 	from test_ffi.rb:28:in `dup'
# # 	from test_ffi.rb:28:in `<main>'
# # free(): double free detected in tcache 2
# # Aborted (core dumped)
# # Same with clone

# val = C.malloc(4)
# p val
# # val.autorelease = false
# p val.dup
# # 1.17.2
# # #<CPtr address=0x0000556540d42870>
# # test_ffi.rb:43:in `initialize_copy': cannot duplicate unbounded memory area (RuntimeError)
# # 	from test_ffi.rb:43:in `initialize_dup'
# # 	from test_ffi.rb:43:in `dup'
# # 	from test_ffi.rb:43:in `<main>'
# # #<FFI::Pointer address=0x0000556540d42870>
# # #<FFI::Pointer address=0x0000556540d42870>
# # free(): double free detected in tcache 2
# # Aborted (core dumped)
# # Same with clone