Process hanging -SIGALRM not delivered- Perl -

i have command i'm executing using open pipe, , want set timeout of 10 seconds , have sub process aborted if execution time exceeds this. however, code causes program hang- why alarm not getting delivered properly?

my $pid = 0; $cmd = "somecommand"; print "running command # $num"; eval {     local $sig{alrm} = sub {                             print "alarm \n";         kill 9, $pid;     };                   alarm 10;     pid = open(my $fh, "$cmd|");     alarm 0; }; if($@) {     die unless $@ eq "alarm \n"; } else {     print $_ while(<$fh>); } 

edit:

so answers below, have:

my $pid = open(my $fh, qq(perl -e 'alarm 10; exec \@argv; die "exec: $!\n" ' $cmd |)); print $_ while(<$fh>); 

but print alarm clock console when alarm times out...whereas dont specify anywhere in code...how can rid of this, , put custom alarm event handler?

thanks!

i want set timeout of 10seconds , have sub process aborted if execution time exceeds this

a different approach set alarm on subprocess itself, handy scripting language have:

my $cmd = "somecommand"; $pid = open(my $child_stdout, '-|',    'perl', '-e', 'alarm 10; exec @argv; die "exec: $!"', $cmd); ... 

your child process perl (well, shell , perl), set alarm on , exec (replace with) $somecommand. pending alarms, however, inherited across exec()s.