fopen status for serial objects

Using R2016a, I'd like to nicely deal with fopen(serial) errors rather than the command window barf at me.

Normal syntax for fopen() includes [fileID,errmsg] = fopen(___)

But the serial version of the command using an object doesn't appear to return anything unless it errors.

>> obj1 = instrfind('Type', 'serial', 'Port', port, 'Tag', '');
>> set(obj1, 'BaudRate', 115200, 'Timeout', 1, 'Terminator','LF');
>> fopen(obj1)
>> 

Note that fopen just happened without saying it worked.

Now, I'll open a TeraTerm session to COM5 and try again...

>> fopen(obj1)
Error using serial/fopen (line 72)
Open failed: Cannot connect to the COM5 port. Possible reasons are another
application is connected to the port or the port does not exist.

As expected. But... how do I deal with these messages programmatically?

>> [fileID,errmsg] = fopen(obj1)
Error using serial/fopen
Too many output arguments.

Nope. Argggg.

Thoughts/Comments/Flames?

Answer 1

[Geoff Hayes]

Could you use a try catch block to try to open the serial object and then, if there is an error, take the appropriate action given the exception?

obj1 = instrfind('Type', 'serial', 'Port', port, 'Tag', '');
set(obj1, 'BaudRate', 115200, 'Timeout', 1, 'Terminator','LF');
try
    fopen(obj1);
catch ME
    fprintf('Could not open serial object because of %s\n', ME.identifier);
    if strcmp(ME.identifier,'<some error identifier>')
        fprintf('Handling exception for %s\n', ME.identifier);
        % perform the appropriate action
    else
        fprintf('Unhandled exception for %s\n', ME.identifier);
    end
end

The '<some error identifier>' would be the error (or errors) that you are interested in.

[C3145]

Perfect. Thank you.

I'm a bit new to this and will dig into the docs on try/catch.