How to Share Data Between These Functions?

Imagine I have myfun1 that loads struct A from disk. I have other functions that should use some fields of A to do some calculations.

function myfun1
global A
A = open( 'C:\A.mat' )
end

function myfun2
global A
A.B = 1;
end

function myfun3
global A
A.C = 2;
end

What is the best solution to allow these functions have access to struct A? I thought of Global Variables, so I make struct A global and then use it wherever I want. Is there a safer and better solution?

Answer 1

[Adam]

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.

[Rightia Rollmann]

Imagine myfun1 is a callback function executed when a user click a button and select MAT File A. What is the best solution to pass A to other functions?

[Steven Lord]

For sharing data among callback functions of graphics objects in particular, see the techniques described in this documentation page.

[Jan]

+1 "Don't use globals" is a very valuable advice.

The topic is discussed frequently. Search in the forum for "share data between callbacks".