Re: [OctDev] is memory leak of figure

[Daniel J Sebald]

On 03/30/2011 09:16 PM, Ben Abbott wrote:
> On Mar 30, 2011, at 9:53 PM, Daniel J Sebald wrote:
>
> > On 03/30/2011 08:45 PM, welkin zzp wrote:
> > > Hi,
> > >       When I close a figure window, I observed that the gnuplot and
> > > gnuplot_x11 processes were always in the system,but didn't work, until
> > > quit octave . I didn't known if it's a memory leak ,but I have to
> > > frequently quit octave after having close few figure windows. The
> > > version of octave is 3.4.0 on ubuntu systerm.
> >
> > Welkin,
> >
> > This topic might be more appropriate for the maintainers list, so I'm cc'ing 
> > there.
> >
> >  From what I recall, Octave currently launches a separate instance of gnuplot 
> > for each figure.  (Because gnuplot only saves the data/state for the most 
> > current plot.)  But I'm not sure if what you describe is the intended behavior 
> > or not, i.e., that gnuplot hangs around in case Octave needs to use it again.  
> > If not, perhaps you could give a more detailed description with examples.  
> > Maybe the behavior can be improved.
> >
> > Dan
>
> Welkin,
>
> When you "close" a figure, do you type ...
>
>         close (hfig)
>
> .... or do you close the figure window using the mouse?
>
> If the first, then the gnuplot session associated with the figure should 
> terminate. However, for the latter, the gnuplot session remains open. Since 
> there is no synchronous communication from gnuplot to octave, there is no 
> method for Octave to become aware that the figure has been closed.
>
> If this functionality is important for you, please try using the fltk backend. 
> This can be turned on by ...
>
>         graphics_toolkit fltk
>
> Ben

Ben,

Should I propose a new feature for gnuplot that will cause an exit if an 
interactive window is closed?  Should it be just X11 or any GUI based 
window?  Or, will there be a remaining issue of a dead end process ID in 
Octave?  Can Octave figure out from the process ID if it is still active 
or not?

Of course, this is sort of a kludge feature because what we really want 
is for gnuplot to save data for each plot so that there is only one 
instance of gnuplot running.

Dan