# yaz_scan

(PHP 4 >= 4.0.5, PECL yaz >= 0.9.0)

yaz_scan — Prepares for a scan

### 说明

yaz_scan ( resource `$id` , string `$type` , string `$startterm` [, array `$flags` ] ) : void

This function prepares for a Z39.50 Scan Request on the specified connection.

To actually transfer the Scan Request to the server and receive the Scan Response, yaz_wait() must be called. Upon completion of yaz_wait() call yaz_error() and yaz_scan_result() to handle the response.

### 参数

`id`

  The connection resource returned by yaz_connect().

`type`

  Currently only type rpn is supported.

`startterm`

  Starting term point for the scan.

  The form in which the starting term is specified is given by parameter `type`.

  The syntax this parameter is similar to the RPN query as described in yaz_search(). It consists of zero or more @attr-operator specifications, then followed by exactly one token.

`flags`

  This optional parameter specifies additional information to control the behaviour of the scan request. Three indexes are currently read from the flags array: number (number of terms requested), position (preferred position of term) and stepSize (preferred step size).

### 返回值

没有返回值。

### 范例

Example #1 PHP function that scans titles

    <?php
    function scan_titles($id, $startterm)
    {
      yaz_scan($id, "rpn", "@attr 1=4 " . $startterm);
      yaz_wait();
      $errno = yaz_errno($id);
      if ($errno == 0) {
        $ar = yaz_scan_result($id, $options);
        echo 'Scan ok; ';
        foreach ($options as $key => $val) {
          echo "$key = $val &nbsp;";
        }
        echo '<br /><table>';
        while (list($key, list($k, $term, $tcount)) = each($ar)) {
          if (empty($k)) continue;
          echo "<tr><td>$term</td><td>$tcount</td></tr>";
        }
        echo '</table>';
      } else {
        echo "Scan failed. Error: " . yaz_error($id) . "<br />";
      }
    }
    ?>