unbind

# File ext/dl/lib/dl/func.rb, line 159
    def unbind()
      if DL.fiddle? then
        if @cfunc.kind_of?(Fiddle::Closure) and @cfunc.ptr != 0 then
          call_type = case abi
                      when CALL_TYPE_TO_ABI[nil]
                        nil
                      when CALL_TYPE_TO_ABI[:stdcall]
                        :stdcall
                      else
                        raise(RuntimeError, "unsupported abi: #{abi}")
                      end
          @cfunc = CFunc.new(0, @cfunc.ctype, name, call_type)
          return 0
        elsif @cfunc.ptr != 0 then
          @cfunc.ptr = 0
          return 0
        else
          return nil
        end
      end
      if( @cfunc.ptr != 0 )
        case @cfunc.calltype
        when :cdecl
          remove_cdecl_callback(@cfunc.ptr, @cfunc.ctype)
        when :stdcall
          remove_stdcall_callback(@cfunc.ptr, @cfunc.ctype)
        else
          raise(RuntimeError, "unsupported calltype: #{@cfunc.calltype}")
        end
        @cfunc.ptr = 0
      end
    end