Trouble with callback with uimenus

function startup

File = uimenu(fig,'Label','File');

Message = uimenu(File,'Label','Message','Callback',@display);

end

function display(hObj,event)

disp('Hello world')

end

When this runs through and I click on the menu I get an error saying the following:

Maximum recursion limit of 500 reached. Use set(0,'RecursionLimit',N)

to change the limit. Be aware that exceeding your available stack space can

crash MATLAB and/or your computer.

Error in CreatingMenus>display

Error while evaluating uimenu Callback

Am I missing something really obvious?

Answer 1

[Jan]

Yes, you are missing something more or less obvious: When a line does not end with an semicolon, the built-in function display() is called to show the results in the command window. When you shadow the original display() function with a user-defined one, this function is called. And when it contains a line without a trailing semi-colon, it calls itself recursively.

Shadowing built-in function is a problem frequently. Therefore I'd avoid names like "display" and "startup" might lead to unexpected effects also.

Btw. you can investigate such problems by using the debugger. Set a breakpoint in the code and step through the program line by line. Then you can find out, where the recursion appears.

[Image Analyst]

Good to know. Sometimes you don't know you've overwritten a built-in function until you have a major fecal/turbine impact. I didn't know display() was a built in function, and only sometimes do I do "which -all myFunctionName" to see if it's a built-in function. I should have noticed startup when I read his post, but I didn't - good catch on your part. He really won the exacta when he picked two reserved function names!