Just tried on my home Ubuntu system (perl 5.8.8). Ran for a few seconds (a new record!) and crashed with 

Unable to create sub named "" at crash.pl line 15.

[download]

This is the exact code I used: 
#!/usr/bin/perl

use warnings FATAL => qw( all );
use strict;

use POSIX qw( :signal_h );

$SIG{ALRM} = sub { print "SIGARLM: main handler\n" };

sub f {
        my $sigset = POSIX::SigSet->new;
        my $blockset = POSIX::SigSet->new( SIGALRM );

        sigprocmask(SIG_BLOCK, $blockset, $sigset );
        local $SIG{ALRM} = sub { print "SIGALRM\n" }; # line 15
        sigprocmask(SIG_SETMASK, $sigset );
}

if (fork) {
        # parent
        f while 1;
} else {
        # child
        sleep 1;
        print "child starting\n";
        1 while kill ALRM => getppid;
}

[download]

In reply to Re^2: Setting signal handlers considered unsafe? by gnosek
in thread Setting signal handlers considered unsafe? by gnosek

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