MATLAB: Do I get a mask display of “???” when I set the Icon & Ports Dialog field with a script that uses &1, &2, &3 notation that is called from the Mask Initialization Tab in Simulink 7.3 (R2009a)

Question

I have a masked subsystem. I wish to update the mask display by calling a script from the Initialization tab. This initialization tab sets the Icon & Ports field with the SET_PARAM command and uses &1, &2 notation to access the dialog parameter fields:

lineInfo = ['fprintf(''%s Seg, Type %s\n%s\n%s\n\n\n'', &2, &1, &4, &3 );' char(10) ];
set_param( theBlk, 'MaskDisplay', lineInfo );

However, when I click Apply, I recieve "???" on the mask. If I click Okay or Update Diagram, the mask resolves correctly and the ??? goes away. Why is this?

Answer 1

The use of &1 and &2 notation to access dialog parameters is not recommended. Instead, use GET_PARAM to access these fields.

           lineInfo = ['fprintf(''%s Seg, Type %s\n%s\n%s\n\n\n'', get_param(gcb, "dialogparameter1"),' ...
                       'get_param(gcb, ''dialogparameter2''), get_param(gcb, ''dialogparameter3''), get_param(gcb, ''dialogparameter4'') );' char(10) ];