Fiddle.last_error

# File tmp/rubies/ruby-3.4.1/ext/fiddle/lib/fiddle.rb, line 57
def self.last_error
  if RUBY_ENGINE == 'jruby'
    errno = FFI.errno
    errno == 0 ? nil : errno
  else
    Thread.current[:__FIDDLE_LAST_ERROR__]
  end
end