# using Sys::Syslog log levels
sub open_db {
    my $dbname = shift;
    # ...
    if (defined $dbh) {
        log_this(LOG_NOTICE, 'OPEN_DB', $dbname, 'db connection established');
    }
    else {
        log_this(LOG_ERR, 'OPEN_DB_NOK', $dbname, 'db connection failed');
    }
}