Assigning tstart to tic, when tic is a timer start function

Hello, Im using a timer object to set some function going with a delay that occurs at a time whilst a loop containing a pause is executed.

app.MessagesTextArea.Value='';
ReportMessage(app,'Starting Timer, msg in 5s');            
% Can use an anonymous function (for the "TimerFcn" callback) that take two input arguments (for "obj" and "event")
% and calls the other function with its corresponding input argument ('msg') 
t = timer('TimerFcn',@(~,~)app.ReportMessage('...Timermsg'),... 
    'StartDelay',5);

% Execute the Timer
start(t);
tstart=tic;

for i=1:20
    ReportMessage(app,num2str(toc(tstart)));
    pause(0.5)
end 

where my function ReportMessage is below.

function ReportMessage(app,msg)
        currString=get(app.MessagesTextArea,'Value');
        %currString=[{char(msg)};currString];  %add to top of message box
        currString=[currString; {char(msg)}];  %add to bottom of message box
        app.MessagesTextArea.Value=currString;
        drawnow;
        scroll(app.MessagesTextArea,'bottom');
end

This works fine, however, sometimes the function I call has a tic in, so this is why I assign tstart to this tic.

Now I realised I can also setup a timerstart function, so i thought it would be better to put the tic inside this to make the start(t) and tic more coincindent in time.

t.StartFcn = @(~,~)tic

This works, but how would I assing tstart to this tic?

Thanks

Jason

[Stephen23]

"This works, but how would I assing tstart to this tic?"

Callback functions are not called with an output argument, so with that function... you can't.

Define a normal function, call TIC, obtain and store its output. Specify that function as the STARTFCN.

[Jason]

Thanks Stephen.

Not sure whare I've gone wrong:

   function tstart=TIC(app)
        tstart=tic;
   end

 t.StartFcn = @(~,~)app.TIC;   
 
 Unrecognized function or variable 'tstart'.

[Jason]

Ah, I haven't stored tstart anywhere!!

When I do this:

properties (Access = public)
    myStart    % To use with tic
end

I can then call it from

app.myStart

This is my full code:

% You can use an anonymous function (for the "TimerFcn" callback) that take two input arguments (for "obj" and "event")
% and calls your other function with its corresponding input argument ('msg') 
t = timer('TimerFcn',@(~,~)app.ReportMessage('...Timermsg'),... 
    'StartDelay',5);
t.StartFcn = @(~,~)app.TIC;
% Execute the Timer

start(t);
% tstart=tic;

for i=1:20
    ReportMessage(app,num2str(toc(app.myStart)));
    pause(0.48)
end     

and it all works. Is this the best/only way to achieve this?

[Stephen23]

"Is this the best way to achieve this?"

Defining the value as an app property seems a like good approach.

[Jason]

Thanks

Answer 1

[Benjamin Kraus]

As @Stephen23 said, if you have an app, storing the output from tic in a property on your app is a good approach. However, another option would be to store the output from tic in the UserData property on the timer object. The UserData property is designed to store arbitrary data associated with the timer, and the start time seems like a good use for that property.

t = timer('TimerFcn',@(t,~) disp(toc(t.UserData)),...
'StartDelay',5,'StartFcn',@(t,~) set(t,'UserData', tic));
start(t)