how to handle serial communications when using timer callbacks

Hello, I am using a timer function to get a callback for a GUI update. In my application there are also some functions that use serial communication. I am afraid of the case, that my program is inside such a function calling the serial commands while getting a timer callback inside it.

fprintf(...)
  ---> let the timer do the callback here, while the fscanf()-command gets lost and the data s well. 
fscanf(...)

is there any way to get an exception for the program being in these functions?

Answer 1

[Thomas]

Got it.

Inside a function, MATLAB will produce an intrinsic mutex, so this won't happen.