Re: [Plplot-general] hard disk filling up

[Maurice L. <mj...@ga...>]

Jay Christnach writes:
 > hello again!
 > to answer my previous question:
 > My 50 channel oscilloscope application is feasible with plplot as graph 
 > library. It is really fast. I use the polygon fill function to erase previous 
 > plotted data.
 > 
 > but another problem:
 > If I let the program run a long time my hard disk fills up. It took some time 
 > to find out what file would get so huge, because the file doesn't show up in 
 > the filesystem, because it is already deleted. (funny phenomenon). 
 > #lsof -c scope
 > COMMAND   PID USER   FD   TYPE     DEVICE       SIZE    NODE NAME
 > (...)
 > scope   32031 root    6u   REG        8,3 1415630848   19684 /tmp/tmpfXiOQuk 
 > (deleted)

Heh.  That looks like the plot buffer.  As you create a plot under X, the plot
buffer pseudo-device is written to, so that on window expose or redraw events,
the prior contents of the window can be recovered.  It's closed at every
end-of-page, and my guess is that you aren't issuing any.. LOL.  There really
should be a size limitation on it though.. >1G is way, way too big. :)

Although there is no API control for this, fortunately you do have access
through the plplot stream pointer.  You can disable writing to the plot buffer
entirely by setting pls->plbuf_write to 0.  Or keep it writing by default but
control its contents through manipulating pls->plbufFile.  See src/plbuf.c for
more info.

-- 
Maurice LeBrun