My functions Won't Share Variables

Hello, I'm a student, attempting to write a data processing program with a GUI. I have an m-file with several functions in it, and I'm using this notation:

function [output variables]=GUI(input variables)

function [output variables]=fun1(input variables)

function [output variables]=fun2(input variables)

function [output variables]=fun3(input variables)

function [output variables]=fun4(input variables)

function [output variables]=fun5(input variables)

I use the GUI to gather all of the parameters for the algorithm functions, and I can't figure out how to get the functions to share variables. I am pretty sure that the scopes of the functions are not overlapping, but I don't know how to make this happen. What is the best way to make them share. Thanks!

Answer 1

[Jan]

You can use GUIDATA to obtain a struct, which is stored in the FIGURE of the GUI. Then all subfunctions need e.g. the figure handle as input and GUIDATA is used to get former values and write new values to the data.

Answer 2

[Doug Eastman]

You can share the workspace of the main GUI function with the subfunctions fun1-5 by making those subfunctions nested functions. Use the following syntax:

function GUI()
    function fun1()
    end

    function fun2()
    end

    ...
  end

In this case fun1-5 can use any variables in the GUI function without needed to pass them in explicitly.

[Quinn]

I already tried this, and I think maybe then my problem is how I'm calling the functions. There are uicontrols in the GUI which call each function:

function GUI()

uicontrol('callback',@(inputarg)fun1)

...

function []=fun1()

end

Answer 3

[Walter Roberson]

Remember that shared variables must be defined (initialized) before the subfunctions are defined.

Answer 4

[Quinn]

I simply deleted all of the input/output parameters for the subfunctions, and then they were able to freely share variables. It works now, but I'm curious as to why. Thanks for the responses.

function [all variables]=GUIfunction(all variables)

fun1 fun2 fun3 fun4 fun5 end

[Walter Roberson]

Your code in your original question shows the functions as having parameters, but your code in your comment in response to Doug shows your functions as not having any parameters; as the comment was later, I presumed that it was the more precise version.

The variables you were trying to share: were you naming them in the parameter list to fun1 and so on? If you were, then as is described in the documentation for shared variables, variables in a functions parameter list are never shared with variables from the outer scope. By deleting the names from the parameter list, you would have given the functions access to the shared versions of those variable names.

Answer 5

[Image Analyst]

See the FAQ for several methods: http://matlab.wikia.com/wiki/FAQ#How_can_I_share_data_between_callback_functions_in_my_GUI.3F