use strict;
use warnings;
use POSIX;

if (my $pid = fork) {
        sleep 1;
        alarm 10;
        kill (POSIX::SIGUSR2, $pid);
        $SIG{CHLD} = 'IGNORE';
        while( wait() != -1 ){ print STDERR "wait\n"};
} else {
        $SIG{USR2} = sub {
                print "CHILD $$ EXIT\n";
                exit(1);
        };
        sleep 1 while (1);
}

print STDERR "DONE\n";

[download]

This code dies with ALARM, only on OpenBSD, only on Perl 5.12.x. (installed with perlbrew)

And it usually works well with openbsd vendor perl 5.12.2: 

  Locally applied patches:
        CVE-2010-0405
        Updated CGI to 3.51
        Updated Test::Simple to 0.98
        Updated List::Util to 1.23
        CVE-2011-1487
        Updated Digest to 1.17
        CVE-2011-2939
        uncommitted-changes

[download]

Note that $SIG{CHLD} = 'IGNORE'; is a special perl feature to auto-reap zombies (i.e. it acts as calling wait() in signal handler), however replacing $SIG{CHLD} = 'IGNORE' with: 

 $SIG{CHLD} = sub { while( wait() != -1 ){ print STDERR "wait0\n"}; };

[download]
fixes problem

I am wondering is this a bug or feature and mixing wait() in signal handlers and wait() in main code is bad idea?

In reply to SIG CHLD IGNORE and wait at same time by vsespb

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