>
> > Could anybody show me how to use the alarm command
> of ksh?
> > I don't quiet understand the output of alarm --man:
> > # alarm --man
> > Usage: alarm [-r] [varname seconds]
> >
> > Knut
> >
>
> alarm hasn't been documented because it is not
> working in all cases.
>
> Here is an example of code that shows how it is
> supposed to work:
> =======================cut
> here==============================
> alarm -r tbar +10
> tbar.alarm()
> {
> printf $'\E]0;%T %s\a' now "$PWD"
> =================cut
> here==============================
>
> This code sets an alarm that goes off every 10
> seconds. By defining
> an alarm variable with alarm, you can specify a
> callback function var.alarm
> that will execute when the alarm expires.
>
> In this case the title bar is updated with the
> current time and the
> current working directory every 10 seconds.
>
> David Korn
> dgk at research.att.com
I see that the connection nbetween the variable and the callback function is
dependent on the order of the commands; absent an "alarm var N" command,
$ function bogus.alarm
More? {
More? date
More? }
ksh93: bogus.alarm: invalid discipline function
But in another order different from the original example:
alarm -r junk +2
function junk.alarm
{
date
}
alarm -r junk +1
the 2nd alarm command doesn't remove the existing junk.alarm function, but
doesn't make use of it either. By comparision, a var.set function seems to
disappear
if the corresponding var is unset.
Whatever the proper understanding of the relationship between variables and
discipline
functions might be, I'd feel a lot better if it were more clearly spelled out;
and if alarm
is one day to become documented, that it be more consistent between alarm and
other
discipline functions (or else described in enough detail to understand the
difference).
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