use constant INTERVAL => 3600;

my %alerts;
sub wrapSendSMS{
    my( $alert, $no ) = @_;

    ## Do nothing if we've sent one recently
    return if exists $alerts{ $alert } 
    	  and time() - $alerts{ $alert } < INTERVAL;
    
    ## Send it and record when
    sendSMS( $alert, $no );
    $alerts{ $alert } = time;
    return 1;
}