gnuplot-beta

Re: breaking out of script

[Hans-Bernhard B. <br...@ph...>]

On Sun, 12 Sep 2004, Daniel J Sebald wrote:

> I've spruced up the Tcl/Tk demo a bit.  A list box selects the demo to 
> run.  There is the "Next" button that Donald included.  I want to 
> include a "Stop" button for breaking out of the demo.  In other words, I 
> want the "Stop" button to behave as a cntrl-C to gnuplot.  Any idea of 
> how to do that from a non-command-line environment?  I'm guessing that 
> may be system dependent.  Is there an escape character I can send to 
> gnuplot when in pause mode that will stop it executing any script files? 

Send a SIGINT to the child?  Send it a literal Ctrl-C character?
Send it an 'exit' or 'quit' command?

-- 
Hans-Bernhard Broeker (br...@ph...)
Even if all the snow were burnt, ashes would remain.

Re: breaking out of script

[Daniel J S. <dan...@ie...>]

Hans-Bernhard Broeker wrote:

>Send a SIGINT to the child?  Send it a literal Ctrl-C character?
>Send it an 'exit' or 'quit' command?
>

Ethan suggested SIGINT.  Those literal characters are treated simply as 
any other character by "pause".  I needed something to break out of the 
current running demo, to start a different demo.

proc loadDemo {x y} {
    global dirName
    global gpfd

    # Send ctrl-C to gnuplot in case a different demo is running.
    exec kill -INT [pid $gpfd]
    set file [file join $dirName [.sel.f.list get @$x,$y]]
    gnuplot "load \"$file\""
}

But thinking about this right now.  I bet there may be an issue with 
timing.  The "kill" command is system level and that doesn't necessarily 
complete before Tcl/Tk stuffs "load \"$file\"" into the pipe.  So, what 
could happen occassionally is the SIGINT happens _after_ some characters 
move through the pipe and the command gets partially destroyed, 
confusing gnuplot.  Hmmm...

Dan