change input during Timer function is running

Hi, i have like below:

    function paus(src,evt,b)
    c=b+1;
    display(b);
    end

and my timer is:

a = timer('ExecutionMode','fixedRate','Period',0.065,'TimerFcn',@(~,~)paus(src,evt,b))

The question during timer is running, i want to keep changing the value of input (variable b). However, the result still shows the initial value of b (eg b=1, thus c=2) and the result (variable C) is not changing. why is that? can i change any input of my function during timer is running?

is urgent!

please help

thank you!