How do I programatically initialize a M-S-Function in a Library?

I am trying something which is somewhat complicated, so please bear with me!

For our customers, we wish to supply a generic M-File S-Function and a script that will generate a Simulink Library containing a S-Function block (using the M-file) with parameters based on their input.

The library and the Simulink blocks it contains are generated programatically (using new_system, add_block, etc) by the generation script.

My M-S-Function defines the number of input ports and output ports in the setup function, based on Dialog parameters.

i.e., in my_sfcn.m:

   function my_sfcn(block)
   setup(block);
   %endfunction

   function setup(block)
   % parameters:
   % 1 - names of output ports (cell array of strings)
   % 2 - names of input ports (cell array of strings)
   block.NumDialogParams = 2;

   out_names = block.DialogPrm(1).Data;
   in_names = block.DialogPrm(2).Data;

   % Set up number of input and output ports
   block.NumInputPorts = length(in_names);
   block.NumOutputPorts = length(out_names);

   % ... rest of setup ...

I am then (in the generation script), creating the Library as follows:

   new_system('mylib', 'Library')
   add_block('built-in/M-S-Function', 'mylib/mysfcn_block',
             'FunctionName', 'my_sfcn', 'Parameters', my_params)

Where `my_params` is the parameters of the S-Function (output port names and input port names)

The problem now is if I attempt to connect the ports that I know are there, any beyond the first will cause an error:

   add_block('built-in/Inport', 'mylib/in1')
   add_line('mylib', 'in1/1', 'mysfcn_block/1')
   add_block('built-in/Inport', 'mylib/in2')
   add_line('mylib', 'in2/1', 'mysfcn_block/2')
   Invalid Simulink object name: mysfcn_block/2.

This is because the M-S-Function has not been initialized (setup has not been called yet) so the number of ports has not been correctly updated in the added Simulink block.

Is there a programatical way that I can initialise the M-S-Function block and call setup()?

Or is there a parameter I can set that will make the block have the correct number of input and output ports? (something equivalent to block.NumInputPorts, but able to be set via add_block() or set_param())

I can't compile the model (using the technique described on http://www.mathworks.com.au/help/simulink/slref/model_cmd.html ) as this is taking place inside a Library and not a Model, so I am hoping there is another way to make the added S-Function block have the correct number of ports.

Note that I do not know how many ports there will be before the Library generation script is run, my customer will supply this in a configuration file and they will run the generation script.

I am using MATLAB R2010bSP1 and R2011b on Windows and Linux

Answer 1

[Danny S]

I've managed to discover an answer to my own question, thanks to: http://www.mathworks.com.au/help/simulink/sfg/input-and-output-ports.html#f4-90846

Essentially, what I need to do is:

   set_param(blockname,'MaskSelfModifiable','on')

And with this parameter set, the S-Function block updates its number of ports as per specified in setup().