Perl Timers and command-line processes

E-Bitch has asked for the wisdom of the Perl Monks concerning the following question:

So, after a brief respite, I've returned, refreshed.

And, unfortunately, as usual, with problems:

I have this program, sort of a wrapper, if you will, written in Perl, that scans a directory for PostScript files, and for each one found, asks the user weather or not to convert it to a .PDF file, using the underlying unix / adobe distill command. Well, our version of distill is waaaay out of date, and certain PostScript level files cause distill to hang (I believe level 1, but for some reason, 2 & || 3 dont). Is there a way, other than having the user Control-C out of the program, change the name of the file, and rerun the program, to detect how long the distill command has taken, or if it has a problem (there is no error produced, just a hanging sensation.)?

If there is, I'd like to implement it, and halt the distill process, inform the user of the error, and go on about our merry business...

Thanks in advance,

E-Bitch
_________________________________________
E-Bitch
Tempora Mutantur Nos et Mutamur in Illis
"The Times are Changed Even as We are Changed in Them"

Comment on Perl Timers and command-line processes

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Re: Perl Timers and command-line processes
by grep (Monsignor) on Jan 17, 2002 at 04:11 UTC

alarm

eval {
        local $SIG{ALRM} = sub { die "alarm\n" }; # NB: \n required
        alarm $timeout;
        $nread = sysread SOCKET, $buffer, $size;
        alarm 0;
    };
[download]

CAVEAT:

grep

grep> cd pub grep> more beer

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[d/l]

Re: Perl Timers and command-line processes
by kschwab (Vicar) on Jan 17, 2002 at 04:10 UTC

#!/usr/bin/perl -w
use strict;
use POSIX qw(:sys_wait_h);
my $TIMEOUT=180;# or whatever
my $start=time;
if (my $pid = fork) {
    #parent
    while (1) {
        if (waitpid($pid,WNOHANG) == -1) {
            # child is done
            exit;
        } 
        if ( time > ($start + $TIMEOUT)) {
            # time has expired, kill the child
            # this is probably too simplistic, 
            # as the child could ignore the SIGTERM
            kill(15,$pid);
            exit;
        }
        sleep(1);# avoid the tight loop
    }
} else {
    # child
    exec('/some/program');
}
[download]

[reply]
[d/l]

Re: Perl Timers and command-line processes (boo)
by boo_radley (Parson) on Jan 17, 2002 at 03:58 UTC

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Re: Perl Timers and command-line processes
by perrin (Chancellor) on Jan 17, 2002 at 04:13 UTC

alarm

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