# [fpc-devel] What is the meaning of this error Message ?

Vincent Snijders vsnijders at quicknet.nl
Fri Jun 30 20:51:22 CEST 2006

```ik wrote:
> Hi,
>
> I'm trying to translate the following error message:
>
> parser_e_ill_msg_param=03144_E_Message handlers can take only one call
> by ref. parameter
> % A method declared with the \var{message}-directive as message handler
> % can take only one parameter which must be declared as call by reference
> % Parameters are declared as call by reference using the
> \var{var}-directive
>
> And I can't seems to understand it's meaning. Can you please explain it
> to me ?
>

Correct:
TTest = class
private
procedure CMTest(var Msg: TMessage); message CM_TEST;
end;

Incorrect
procedure CMTest(Msg: TMessage); message CM_TEST;
or
procedure CMTest(var Msg: TMessage; i: integer); message CM_TEST;

etc.

The signature of a message handler is fixed.

Vincent

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