How can I use try/catch with conditions?

Hello,

I'd like to execute the following logic:

try
    my_function(1) % connect with a certain utility
    
    if errorMsg == 'verySpecificError' % checks if the utility is already connected
        my_function(0) % first disconnect from utility and re-try to connect again
        
        try
            my_function(1) % try to connect again with utility (after verified it's in dis-connected mode)
        catch 
            disp('problem with utility connection') % meaning there is another issue with connection.
        end
    else
        disp('problem with utility connection') % meaning there is another issue with connection.
    end
end

The purpose of the above is:

1. Try to connect

2. If there is a problem, check if it's the unique case of "you can't connect, since you're already connected".

3. If indeed, you're already connected, disconnect first, and try to connect again.

4. If there is still a problem, display an error/warning.

Answer 1

[Walter Roberson]

try
   my_function(1)
catch ME
  if strcmp(ME.message, 'specific')  
   ...
  end

https://www.mathworks.com/help/matlab/ref/mexception.html

Note that it is better to use a message identifier so that you do not have to worry about the message having data formatted into it, and do not have to worry that the text might have been internationalized into a different language. end

[Mark Golberg]

Thanks! Exactly what I was looking for.

BTW: I'm using 'message' and not 'identifier' since it's not a standard MATLAB error, thus it doesn't gives me any identifier (empty cell).

[Walter Roberson]

If you have control over that function, I would recommend coding the error() to include an identifier. You can make up your own identifiers (as long as they do not conflict with the Mathworks ones.)