Beefy Boxes and Bandwidth Generously Provided by pair Networks
laziness, impatience, and hubris

Re^2: Backticks and SIGALRM

by nemo (Sexton)
on Aug 20, 2007 at 15:35 UTC ( #633850=note: print w/replies, xml ) Need Help??

in reply to Re: Backticks and SIGALRM
in thread Backticks and SIGALRM

Thanks for your reply, it's a working solution to the problem. :)
Many thanks for all replies.


Replies are listed 'Best First'.
Re^3: Backticks and SIGALRM
by BrowserUk (Pope) on Aug 20, 2007 at 16:48 UTC

    YW. Here's a slightly cleaner implementation. The only caveat is that it abitrarially throws away any output received prior to the timeout occuring. Only you can decide how you want to signal timeout if you also wish to retrieve any partial output.

    I guess this could form the basis of a whole CPAN module, but it just seems altogether too trivial for that?

    #! perl -slw use strict; $|++; my $extApp = q[ perl -lwe"$|++; print $_ and sleep 1 for 1 .. 10" ]; for my $timeout ( map $_*2, 4,5,6 ) { my @results = timedCommand( $extApp, $timeout ); if( @results ) { print "Command returned\n", join '', @results; } else { print "Command timed out after $timeout seconds"; } } sub timedCommand { use threads; use threads::shared; my( $cmd, $timeout ) = @_; my @results :shared; my $pid :shared; async { $pid = open my $fh, "$cmd |" or die "$!, $^E"; @results = <$fh>; }->detach; kill 0, $pid while sleep 1 and $timeout--; kill 3, $pid and return if $timeout; return @results; } __END__ c:\test>junk6 Command timed out after 8 seconds Command returned 1 2 3 4 5 6 7 8 9 10 Command returned 1 2 3 4 5 6 7 8 9 10

    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
      The only problem I had with your code was the sleep delay was too long. :) The script was executing over tens of thousands of files so in the end I used the implementation below.
      sub executeTimed{ my $cmd = shift; $|++; my @results :shared; my $pid :shared; async { $pid = open my $fh, "$cmd |" or die "$!, $^E"; @results = <$fh>; }->detach; select(undef, undef, undef, 0.08); my $test = kill (0, $pid); if($test){ kill (3, $pid); push(@results, "Function timed out."); } return pop(@results); }
      Thanks again for all replies.
      I was looking to use default active state perl package and was unsure if ipc-run would execute.


Log In?

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://633850]
Jar. Jar!...

How do I use this? | Other CB clients
Other Users?
Others about the Monastery: (2)
As of 2018-02-19 06:40 GMT
Find Nodes?
    Voting Booth?
    When it is dark outside I am happiest to see ...

    Results (258 votes). Check out past polls.