Problem with Undefined variable or class

Matlab can't see defined struct variable. And I inform you that i had connection with Robot in that time. I apologize for so many posts from me i'm not that good at programming. P1 = rpoint(kwadrat_zolty.Centroid_x*kalibracja,kwadrat_zolty.Centroid_y*kalibracja,-15.600,0,0,0,'signal',[9,-10],'pulse',[1 0.5],'wait',5); % pobranie

If someone don't know what is rpoint I wrote about it here: https://www.mathworks.com/matlabcentral/answers/378570-how-to-get-data-values-from-struct-and-save-it-in-struct?s_tid=prof_contriblnk

Answer 1

[Guillaume]

The variable exists in your workspace, but the error is telling you that in the callback function it does not exist. Functions have their own workspace and if you don't pass them the variables explicitly they can't access them.

Without seeing the callback code and the line where you call that callback it's difficult to tell you how to fix it.

[Damian]

Ok i repaired it. I had to use one more time

evalin('base',' ');

for my "invisible" missing structure to this callback button. Thanks.

[Stephen23]

Rather than using inefficient and buggy methods of passing data between callbacks and workspaces (e.g. evalin and assignin), you would be much better off using better (simpler, more efficient, easier to debug) methods, such as guidata or nested functions. Read more in the MATLAB documentation:

https://www.mathworks.com/help/matlab/creating_guis/share-data-among-callbacks.html

And also read why magically throwing data into other workspaces (e.g. evalin or assignin) is not recommended (unless you want to write slow, buggy, complex code that is hard to debug):

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval