how to use a variable returned from one callback function in an other callback funtion in GUI??

I have two functions called sum1_Callback and disp_Callback

function c=sum1_Callback(hObject, eventdata, handles) c= 2*2;

function disp_Callback(hObject, eventdata, handles,c) disp(c)

In sum_Callback, I have a variable c which I want to use in disp_Callback, but I get an error telling the variable is undefined.

What should be done??

Thanks in advance for the help.

Answer 1

[Walter Roberson]

There are no callbacks that take eventdata as the second parameter and return values. The only callbacks that return values are the ones that are acting as filters, such as a constraint function programmed to ensure that a rectangle selection retains a particular proportion.

[Subhiksha]

Can you please give me a detailed example?