Return inserted serial from drupal_write_record

Question

I have a module which creates records in the db via drupal_write_record and this works perfectly. However I need to get the automatically assigned serial number for each record which is written into a variable.

Does anyone know how I can achieve this and get the index #?

I need the index variable to use in another table to create the reference...

Edit: Clives answer worked as below:

// Create object
$call = new stdClass;  
$call->uid = $user->uid;
$call->call_type = $call_type;
$call->cli = $cli;
$call->start_nid = NULL;
$call->timestamp = $timestamp;

// Insert call row in db  
drupal_write_record($table,$call);

// Test correct index
drupal_set_message($call->call_id);

Answer 1

drupal_write_record() populates the serial field of an object you pass to it automatically. So assuming you have a serial field in your table called id, if you run code like the following:

$record = new stdClass;
$record->title = 'Title';
$record->some_other_field = 'Something';

drupal_write_record('table_name', $record);

the $record object will be auto-populated with a member representing the serial column when the function returns. In this example you can access it with $record->id.

Answer 2

Think I found the solution:

$last_id = db_last_insert_id($table, $field);

Edit: As per Clive's comments his solution above is most effective.