Closing MATLAB GUI application programmatically without using error() -

i trying make application/gui closes if user clicks cancel or exit of input dialog. tag of gui called window using close(handles.window); leads program looping through once , (after user clicks cancel or exit again) reaching close(handles.window); line which, of course, leads invalid figure handle error.

is there method close application without need producing error , not closing entire matlab environment (like quit , exit). error() temporary fix works don't want application seem has crashed.

i have tried close has no effect. it's worth noting application reach inside if statement if user clicks cancel or exit.

i have tried setting variable , having close commands outside while loop.

apa = getavailablecomport(); aplist = '';  = 0; idx = 1:numel(apa)     if == 0         aplist = apa(idx);     else         aplist = strcat(aplist, ', ', apa(idx));     end     = + 1; end  prompt = {'enter com port:'}; title = 'com port'; num_lines = 1; def = aplist; com_port = inputdlg(prompt,title,num_lines,def);  % keep asking com port number until user gives valid 1 while sum(ismember(apa, com_port)) == 0 % if com port comes in available com ports @ least once     % if user clicks cancel, close guide     if isempty(com_port) == 1         error('closing...'); % here problem     end     prompt = {'invalid com port'};     title = 'invalid com port';     com_port = inputdlg(prompt,title,num_lines,def);     end 

the function getavailablecomport found @ http://www.mathworks.com/matlabcentral/fileexchange/9251-get-available-com-port

this entire piece of code @ top of gui_openingfcn() function.

have tried putting break after close(handles.window). break exit while loop won't hit line again.

if isempty(com_port) == 1     close(handles.window)     break end 

this way while loop stops after closing window. if need more cleanup besides closing window set error flag .

%above while loop errorflag = false;  if isempty(com_port) == 1     close(handles.window)     errorflag = true;     break end  %outside of while loop if errorflag     %do more clean-up / return / display error or warning end 

also fyi, don't need isempty(com_port) == 1 ... isempty(com_port) return true/false without == 1