MATLAB Central Newsreader - how to stop execution

how to stop execution

Todd Welti — Wed, 11 Mar 2009 21:03:00 -0400

This might seem like a dumb question, but how do you stop code execution? I dont mean 'return', or 'dbstop', or 'error'. I just want to stop the code immediately, with no fanfare and just return to the command line. Strangley enough, i can't seem to find a command that does this! "Return" doesn't necessarily work if the current function is not the main function. "dbstop" puts it in debug mode. "quit" quits matlab.

I've looked and looked and can't find this simple command.

Re: how to stop execution

Walter Roberson — Wed, 11 Mar 2009 21:44:29 -0400

Todd Welti wrote:
> This might seem like a dumb question, but how do you stop code execution? I dont mean
> 'return', or 'dbstop', or 'error'. I just want to stop the code immediately, with no
> fanfare and just return to the command line.

There isn't a way: all of those routines have to be unwound and their workspaces
cleaned up, which might invoke exit handlers, and so on.

The closest I can think of is to have your main routine have a try/catch
and then when you wish to abort, error() the particular string that the
catch is keyed for, and when you detect it, bail out cleanly from your
main routine.

Re: how to stop execution

Matt Fig — Wed, 11 Mar 2009 22:05:05 -0400

ctrl+c

Re: how to stop execution

Todd Welti — Wed, 11 Mar 2009 23:50:21 -0400

"Matt Fig" <spamanon@yahoo.com> wrote in message <gp9cig$lul$1@fred.mathworks.com>...
> ctrl+c

I meant a command that would be in the code.

Re: how to stop execution

Todd Welti — Wed, 11 Mar 2009 23:52:02 -0400

Walter Roberson <roberson@hushmail.com> wrote in message <XgWtl.34251$l71.6225@newsfe23.iad>...
> Todd Welti wrote:
> > This might seem like a dumb question, but how do you stop code execution? I dont mean
> > 'return', or 'dbstop', or 'error'. I just want to stop the code immediately, with no
> > fanfare and just return to the command line.
>
> There isn't a way: all of those routines have to be unwound and their workspaces
> cleaned up, which might invoke exit handlers, and so on.
>
> The closest I can think of is to have your main routine have a try/catch
> and then when you wish to abort, error() the particular string that the
> catch is keyed for, and when you detect it, bail out cleanly from your
> main routine.

Yes, that should work. is it just me or is it strange that there is not such a command - like ctrl c, but useable in an mfile?

Re: how to stop execution

Jos — Thu, 12 Mar 2009 07:54:04 -0400

"Todd Welti" <twelti@harman.com> wrote in message <gp9ir2$kcf$1@fred.mathworks.com>...
> Walter Roberson <roberson@hushmail.com> wrote in message <XgWtl.34251$l71.6225@newsfe23.iad>...
> > Todd Welti wrote:
> > > This might seem like a dumb question, but how do you stop code execution? I dont mean
> > > 'return', or 'dbstop', or 'error'. I just want to stop the code immediately, with no
> > > fanfare and just return to the command line.
> >
> > There isn't a way: all of those routines have to be unwound and their workspaces
> > cleaned up, which might invoke exit handlers, and so on.
> >
> > The closest I can think of is to have your main routine have a try/catch
> > and then when you wish to abort, error() the particular string that the
> > catch is keyed for, and when you detect it, bail out cleanly from your
> > main routine.
>
> Yes, that should work. is it just me or is it strange that there is not such a command - like ctrl c, but useable in an mfile?

help keyboard

(or modify finish.m and use quit cancel)

hth
Jos

Re: how to stop execution

Peter O'Connor — Wed, 31 Mar 2010 18:27:07 -0400

Here's what I use to do that (a little roundabout because, ridiculously, it requires that the user confirm that you'd like to quit)

disp('You chose to cancel. Quit the program now?');
disp('<a href="MATLAB: dbquit;">Yes</a> / <a href="MATLAB: dbcont;">No</a>');
keyboard;

"Jos " <#10584@fileexchange.com> wrote in message <gpaf2s$hc1$1@fred.mathworks.com>...
> "Todd Welti" <twelti@harman.com> wrote in message <gp9ir2$kcf$1@fred.mathworks.com>...
> > Walter Roberson <roberson@hushmail.com> wrote in message <XgWtl.34251$l71.6225@newsfe23.iad>...
> > > Todd Welti wrote:
> > > > This might seem like a dumb question, but how do you stop code execution? I dont mean
> > > > 'return', or 'dbstop', or 'error'. I just want to stop the code immediately, with no
> > > > fanfare and just return to the command line.
> > >
> > > There isn't a way: all of those routines have to be unwound and their workspaces
> > > cleaned up, which might invoke exit handlers, and so on.
> > >
> > > The closest I can think of is to have your main routine have a try/catch
> > > and then when you wish to abort, error() the particular string that the
> > > catch is keyed for, and when you detect it, bail out cleanly from your
> > > main routine.
> >
> > Yes, that should work. is it just me or is it strange that there is not such a command - like ctrl c, but useable in an mfile?
>
> help keyboard
>
> (or modify finish.m and use quit cancel)
>
> hth
> Jos

Re: how to stop execution

Todd Welti — Wed, 31 Mar 2010 19:02:20 -0400

"Peter O'Connor" <peter.oconnor@mail.mcgill.ca> wrote in message <hp045r$h0$1@fred.mathworks.com>...
> Here's what I use to do that (a little roundabout because, ridiculously, it requires that the user confirm that you'd like to quit)
>
> disp('You chose to cancel. Quit the program now?');
> disp('<a href="MATLAB: dbquit;">Yes</a> / <a href="MATLAB: dbcont;">No</a>');
> keyboard;
>
Yes, that is slightly easier than using keyboard, then having the user type dbquit, but still not very clean. Plus I get a web browser opened up when I tried it. Not sure what would happen for compiled code.

Looking back in this thread (and one other on tis subject) I see several suggestions to use try/catch. That's fine if your not in a subfunction or subsubfunction. The last time I had this problem, not only was I in a sub sub funciton, but complicated by the fact that it was called from a GUI callback anonymous funciton. I suppose you could have each subfunction returning a success/failed (0 or 1) as is often done anyway. Then bailing out of a subsub function would result in clean bail out of main.

Re: how to stop execution

Walter Roberson — Wed, 31 Mar 2010 19:47:45 -0400

Peter O'Connor wrote:
> Here's what I use to do that (a little roundabout because, ridiculously,
> it requires that the user confirm that you'd like to quit)
>
> disp('You chose to cancel. Quit the program now?');
> disp('<a href="MATLAB: dbquit;">Yes</a> / <a href="MATLAB:
> dbcont;">No</a>');
> keyboard;

Testing in 2008b, I found that I had to use lower-case for that matlab. Also,
the space after the colon was not required but was accepted.

disp('<a href="matlab:dbquit;">Yes</a> / <a href="matlab:dbcont;">No</a>');

When I used MATLAB: then the help browser would complain that matlab was
unable to link to the document.

Re: how to stop execution

Mike Hoff — Sat, 29 Oct 2011 02:18:15 -0400

"Todd Welti" <twelti@harman.com> wrote in message <gp98u4$g9h$1@fred.mathworks.com>...
> This might seem like a dumb question, but how do you stop code execution? I dont mean 'return', or 'dbstop', or 'error'. I just want to stop the code immediately, with no fanfare and just return to the command line. Strangley enough, i can't seem to find a command that does this! "Return" doesn't necessarily work if the current function is not the main function. "dbstop" puts it in debug mode. "quit" quits matlab.
>
> I've looked and looked and can't find this simple command.

I'm going to use

error('I don't want to play anymore')

It's quick and dirty, with red and errors and beeping, but it's better than a fancy loop, or commenting everything out

Re: how to stop execution

Radek — Sat, 28 Jan 2012 21:45:11 -0500

Re: how to stop execution

Todd Welti — Mon, 30 Jan 2012 21:17:11 -0500

"Radek " <dzidmail@gmail.com> wrote in message <jg1q97$gv7$1@newscl01ah.mathworks.com>...
> "Todd Welti" <twelti@harman.com> wrote in message <gp98u4$g9h$1@fred.mathworks.com>...
> > This might seem like a dumb question, but how do you stop code execution? I dont mean 'return', or 'dbstop', or 'error'. I just want to stop the code immediately, with no fanfare and just return to the command line. Strangley enough, i can't seem to find a command that does this! "Return" doesn't necessarily work if the current function is not the main function. "dbstop" puts it in debug mode. "quit" quits matlab.
> >
> > I've looked and looked and can't find this simple command.
>
> command:
> break

do you know what the break command does?!?!? This would not work at all.

BREAK Terminate execution of WHILE or FOR loop.
    BREAK terminates the execution of FOR and WHILE loops.
    In nested loops, BREAK exits from the innermost loop only.

    BREAK is not defined outside of a FOR or WHILE loop.
    Use RETURN in this context instead.