How to get port names for built-in blocks?

This is how I find port names in my Simulink model:

function [portNames] = findOutputPortNames(obj)
    % Lists output port names for the target module.
    simBlockH = get_param(target_module, 'Handle');
    portH = find_system(simBlockH, 'LookUnderMasks', 'on', 'FollowLinks', 'on', 'SearchDepth', 1, 'BlockType', 'Outport');
    portNames = cellstr(get_param(portH, 'Name'));
end

This works fine for my subblocks.

However, it does not work for blocks that are builtin, for example "Biquad Filter".

How do I get output (or input) port names for built-in blocks?

The above find_system() call returns empty result.

When I remove the BlockType parameter:

portH = find_system(simBlockH, 'LookUnderMasks', 'on', 'FollowLinks', 'on', 'SearchDepth', 1);
portNames = cellstr(get_param(portH, 'Name'));

I get the following output:

portNames =
  5×1 cell array
    {'PH20hz'}
    {'Signal_in'}
    {0×0 char}
    {0×0 char}
    {'Signal_out'}

How do I find out which are input ports, and which are output ports?

Or, instead of 'BlockType', 'Outport', should I use somethig else for 'BlockType'?

[Fangjun Jiang]

That is not port name. That is under masks Inport/Outport block name. Port names, if they exist, are different. What name you really want for built-in blocks?

[Danijel Domazet]

Hi Fangjun,

I need output port/wire/link name.

After some experimenting, I found this works:

open_system(test_model, 'loadonly');
...    
bt = get_param(target_module, 'BlockType');
if bt == "S-Function"
    portNames = get_param(target_module, 'OutputSignalNames');
end
...
close_system(test_model, 0)