Detect warning and take action

Question

1 个投票

I have a for loop and I call a function inside it. What I want to do, is detect if this function call created any warnings and if so continue. Something like:

for i=1:len
   c = my_func1(arguments);
   if (any warning)
       continue;
   end
end

Any suggestions? I tried to use lastwarn, without success though.

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Answer 1

Cam Salzberger 2017-11-2

在 MATLAB Online 中打开

11 个投票

Hello Ioannis,

A common workflow is to use lastwarn in this way:

for ...
    warning('') % Clear last warning message
    ... run code ...
    [warnMsg, warnId] = lastwarn;
    if ~isempty(warnMsg)
        ...react to warning...
    end
end

But you said lastwarn didn't work for you. How did you use it? What do you mean it didn't work? What kind of warnings were you seeing that weren't being picked up?

-Cam

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Ioannis Nemparis 2017-11-2

I was incorrectly clearing last warning message by doing warnMsg=[] and warnId =[]; Let me experiment a bit with your answer and I will upvote you soon enough

Rookienp 2019-6-5

Suggestion in the Matlab 2018b editor:

WARNING('') does not reset the wanring state, use LASTWARN('') instead.

Both ways work though.

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Answer 2

Guillaume 2017-11-2

编辑：Guillaume 2017-11-2

4 个投票

You can treat warnings as errors and thus catch them with a try ... catch statement, however, it is undocumented and may break in a future version. On the other hand, it's been there since 2004.

For more details, see Yair's blog.

However, if you want to catch all warnings, you'll have to set them to error one by one since warning('error') or warning('error', 'all') is not supported, just warning('error', specificmsgid).