Re^3: protect children from SIG{INT}

If a sleeping process catches any signal, it doesn't automatically resume sleep after the handler fires. Your process is exiting because it's done.

To sleep a specified time in spite of interrupts, you need to be prepared to resume sleep. One way in Perl,

my $span = 5;
$span -= sleep $span while $span > 0;
[download]

The solution I gave would be improved by doing that wherever sleep 5 appears.

After Compline,
Zaxo

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Re^4: protect children from SIG{INT} by QM (Parson) on Nov 18, 2005 at 15:12 UTC
`$span -= sleep $span while $span > 0;` [download] Thanks, I had forgotten that `sleep` returns something useful! -QM -- Quantum Mechanics: The dreams stuff is made of	[reply] [d/l] [select]
Re^4: protect children from SIG{INT} by sgifford (Prior) on Nov 18, 2005 at 16:18 UTC
It still looks to me like the `exec` is the problem: `#!/usr/bin/perl $SIG{INT} = $SIG{HUP} = sub {}; exec 'perl', '-e', '$span=5; $span -= sleep $span while $span > 0; warn "Sleep is done\n";' or die 'exec failed';` [download] Hitting CTRL-C kills the process, and doesn't print `Sleep is done`, as it would if it had completed normally. Of course, using `do` instead would work, because it would avoid the `exec`. Does it even make sense for a signal handler to persist across an `exec`? A signal handler is basically an address in memory that the kernel should cause the user process to jump to if a signal arrives, but after an `exec` the address space will change, and the old address will almost certainly not be a sane place to jump to.	[reply] [d/l] [select]