What you want here is eval.

An example usage might be:

my $timeout = 20;

eval {
    local $SIG{ALRM} = sub { die "timedout" };
    alarm $timeout;
    #Call your subroutine here....
    alarm 0;
};

if ($@) {
    #  $@ will contain error message, if any
}
[download]

Hope this helps,
Darren :)