How can i use a global var with call_back functions?

The problem is: how can i declare a global var, so i can use it on all functions of my guidata?

for example:

function pushbutton5_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton5 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
---->  cpselect(E,D);
guidata(hObject, handles);

% --- Executes on button press in Inserir.
function pushbutton4_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton4 (see GCBO)
% Invoca duas fotos
echo ImRectOpen off;
----->  global E D;
[E,D]=ImRectOpen();

imshow(E,'Parent',handles.axes3);
imshow(D,'Parent',handles.axes4);

set(handles.pushbutton1,'enable','on');
set(handles.pushbutton5,'enable','on');

guidata(hObject, handles);

First, i've ran the pushbutton_callback4 and then pushbutton_callback5. On pushbutton_callback5 global variables (E and D) that were declared on pushbutton_callback4, cant be found.

Answer 1

[Walter Roberson]

http://www.mathworks.com/matlabcentral/answers/19754-declare-variable-accross-all-button