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