module Reline::Terminfo

def self.tigetnum(capname)
  raise TerminfoError, "capname is not String: #{capname.inspect}" unless capname.is_a?(String)
  num = @tigetnum.(capname).to_i
  case num
  when -2
    raise TerminfoError, "not numeric capability: #{capname}"
  when -1
    raise TerminfoError, "can't find capability: #{capname}"
  end
  num
end