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# AutoBill.fetchInvoiceNumbers

Returns an array of `Invoices` matching the search criteria. (If no input parameters are specified, the 12 most recent `Invoice` objects will be returned.)

## Input

*srd*: sparse response description, a SOAP string (which must be a JSON object), in which you specify the elements you want returned.This parameter enables the calling system to constrain a `method` call to return only components you specify. This gives you greater control over returned content, and improves response time within the Vindicia platform by reducing the processing needed for the call.

Some fields are required, either practically or in the WSDL, and will be returned regardless of the *srd*. A null *srd* returns the complete response.

*autobill*: an object of type `AutoBill` that contains the desired invoices.

*invoicestate*: an optional object of type `InvoiceStates`, which limits the returned objects to the specified state: `Open`, `Due`, `Paid`, `Overdue`, or `WrittenOff`.

## Output

*return*: an object of type `Return` that indicates the success or failure of the call.

*invoicenum*: the invoice number which uniquely identifies the fetched invoice within the `AutoBill`.

## Returns

In addition to those listed in [The Return Object](The_Return_Object), this call returns:

| Return Code | Return String |
| - | - |
| `400` | One of the following: - `Unable to load AutoBill: No match.` - `Unable to load AutoBill: *error-description*.` |

## Example

```

$autobill = new AutoBill();
$autobill->set($abID); // for some $abID
$response = $autobill->fetchInvoiceNumbers('Due');
if ($response['returnCode'] == 200) {
   $inv_nums = $response['data']->invoicenum;
   foreach ($inv_nums as $inv_n) {
      // process invoice $inv_n
   }
}
```

**Parent topic:**[AutoBill Methods](../topics/AutoBill_Methods)


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