Problems when re-running matlab gui after closing GUI with exit button

Hi,

I have this code below. My problem is that when I close the Matlab Gui using the exit button in the window (the one similar to an 'x') the next time I try to run matlab, it doesn't work until y press Ctrl+C to stop the execution. I think it is because i'm using Serial communications and the port hasn't been closed, but i'm not completely sure. So, if anyone could help me, I would be very grateful.

function varargout = Medida_Serial_hcsr04(varargin)
% MEDIDA_SERIAL_HCSR04 MATLAB code for Medida_Serial_hcsr04.fig
%      MEDIDA_SERIAL_HCSR04, by itself, creates a new MEDIDA_SERIAL_HCSR04 or raises the existing
%      singleton*.
%
%      H = MEDIDA_SERIAL_HCSR04 returns the handle to a new MEDIDA_SERIAL_HCSR04 or the handle to
%      the existing singleton*.
%
%      MEDIDA_SERIAL_HCSR04('CALLBACK',hObject,eventData,handles,...) calls the local
%      function named CALLBACK in MEDIDA_SERIAL_HCSR04.M with the given input arguments.
%
%      MEDIDA_SERIAL_HCSR04('Property','Value',...) creates a new MEDIDA_SERIAL_HCSR04 or raises the
%      existing singleton*.  Starting from the left, property value pairs are
%      applied to the GUI before Medida_Serial_hcsr04_OpeningFcn gets called.  An
%      unrecognized property name or invalid value makes property application
%      stop.  All inputs are passed to Medida_Serial_hcsr04_OpeningFcn via varargin.
%
%      *See GUI Options on GUIDE's Tools menu.  Choose "GUI allows only one
%      instance to run (singleton)".
%
% See also: GUIDE, GUIDATA, GUIHANDLES

% Edit the above text to modify the response to help Medida_Serial_hcsr04

% Last Modified by GUIDE v2.5 01-Mar-2017 10:33:50

% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name',       mfilename, ...
                   'gui_Singleton',  gui_Singleton, ...
                   'gui_OpeningFcn', @Medida_Serial_hcsr04_OpeningFcn, ...
                   'gui_OutputFcn',  @Medida_Serial_hcsr04_OutputFcn, ...
                   'gui_LayoutFcn',  [] , ...
                   'gui_Callback',   []);
if nargin && ischar(varargin{1})
    gui_State.gui_Callback = str2func(varargin{1});
end

if nargout
    [varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});
else
    gui_mainfcn(gui_State, varargin{:});
end
% End initialization code - DO NOT EDIT

% --- Executes just before Medida_Serial_hcsr04 is made visible.
function Medida_Serial_hcsr04_OpeningFcn(hObject, eventdata, handles, varargin)
% This function has no output args, see OutputFcn.
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% varargin   command line arguments to Medida_Serial_hcsr04 (see VARARGIN)
clear s;
% Choose default command line output for Medida_Serial_hcsr04
handles.output = hObject;

set(handles.guardar,'Enable','off'); 

global stop;
stop = false;
% Update handles structure
guidata(hObject, handles);

% UIWAIT makes Medida_Serial_hcsr04 wait for user response (see UIRESUME)
% uiwait(handles.figure1);

% --- Outputs from this function are returned to the command line.
function varargout = Medida_Serial_hcsr04_OutputFcn(hObject, eventdata, handles) 

varargout{1} = handles.output;

% --- Executes on button press in Medir.
function Medir_Callback(hObject, eventdata, handles)
% hObject    handle to Medir (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
set(handles.Abrir,'Enable','off'); 
global stop
stop=false;

cla reset; %Limpiar la grafica cada vez que se hace click

s = abrir_puerto();

handles.h=animatedline('Marker','o','LineWidth',1,'Color','b');
guidata(hObject,handles);
xlabel('Number of samples','FontSize',16,'FontWeight','bold','Color','w');
ylabel('Distance (cm)','FontSize',16,'FontWeight','bold','Color','w');
set(gca, 'XColor', [1 1 1]);
set(gca, 'YColor', [1 1 1]);

i=1; 

while stop==false
    handles.distancia(i)=fscanf(s,'%d');
    addpoints(handles.h,i-1,handles.distancia(i));    
    drawnow;
    i=i+1; 
end
stop=false;

set(handles.guardar,'Enable','on'); 
set(handles.Abrir,'Enable','on'); 
guidata(hObject,handles);
cerrrar_puerto(s);

% --- Executes on button press in guardar.
function guardar_Callback(hObject, eventdata, handles)
% hObject    handle to guardar (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
dist = handles.distancia;
guardar_archivo(dist);

% --- Executes on button press in Abrir.
function Abrir_Callback(hObject, eventdata, handles)
% hObject    handle to Abrir (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
Abrir_fichero();

% --- Executes on button press in stop.
function stop_Callback(hObject, eventdata, handles)
% hObject    handle to stop (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hint: get(hObject,'Value') returns toggle state of stop
global stop
stop=true;

% --- Executes when user attempts to close figure1.
function figure1_CloseRequestFcn(hObject, eventdata, handles)
% hObject    handle to figure1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% Hint: delete(hObject) closes the figure
delete(hObject);

Thank you

Answer 1

[Image Analyst]

Call fclose() when you shut down the app.