domain.js
function emitError(currentDomain, err) {
    /*jshint camelcase: false*/
    util._extend(err, {
        domain: currentDomain,
        domain_thrown: true
    });
    currentDomain.emit('error', err);
    currentDomain.exit();
}
function emitError(currentDomain, err) {
    /*jshint camelcase: false*/
    util._extend(err, {
        domain: currentDomain,
        domain_thrown: true
    });
    currentDomain.emit('error', err);
    currentDomain.exit();
}
see https://github.com/joyent/node/blob/v0.8.8-release/lib/domain.js#L53