You haven't given any code that calls the functions, but the whole point of functions (or at least one of the main points) is that they take input arguments into a sealed workspace and then provide output arguments. Make use of them - pass your variable as n output argument from myfun1 and then just pass in the variables you need to the other functions, either the full struct or even just certain fields of it. Having a vast amount of data all on one struct is not a good design in the first place so multiple collections of data are generally better.
Don't use global variables though, they are bad for so many reasons (just do a google search or a search on this forum for global variables to see the overwhelming opinion on them) and have no place in proper code design, especially when you can simply pass arguments to a function to achieve the same thing.
