CVIII. YAZ functions


This extension offers a PHP interface to the YAZ toolkit that implements the Z39.50 protocol for information retrieval. With this extension you can easily implement a Z39.50 origin (client) that searches or scans Z39.50 targets (servers) in parallel.

The module hides most of the complexity of Z39.50 so it should be fairly easy to use. It supports persistent stateless connections very similar to those offered by the various SQL APIs that are available for PHP. This means that sessions are stateless but shared amongst users, thus saving the connect and initialize phase steps in most cases.

YAZ is available at You can find news information, example scripts, etc. for this extension at


Compile YAZ and install it. Build PHP with your favourite modules and add option --with-yaz. Your task is roughly the following:

gunzip -c yaz-1.6.tar.gz|tar xf -
gunzip -c php-4.0.X.tar.gz|tar xf -
cd yaz-1.6
./configure --prefix=/usr
make install
cd ../php-4.0.X
./configure --with-yaz=/usr/bin
make install

Runtime Configuration

The behaviour of these functions is affected by settings in php.ini.

Table 1. YAZ configuration options

For further details and definition of the PHP_INI_* constants see ini_set().

Resource Types

This extension has no resource types defined.

Predefined Constants

This extension has no constants defined.


PHP/YAZ keeps track of connections with targets (Z-Associations). A positive integer represents the ID of a particular association.

Example 1. Parallel searching using YAZ()

The script below demonstrates the parallel searching feature of the API. When invoked with no arguments it prints a query form; else (arguments are supplied) it searches the targets as given in in array host.

$num_hosts = count ($host);
if (empty($term) || count($host) == 0) {
    echo '<form method="get">
    <input type="checkbox"
    name="host[]" value="">
        GILS test
    <input type="checkbox"
    name="host[]" value="localhost:9999/Default">
        local test
    <input type="checkbox" checked="1"
    name="host[]" value="">
        BELL Labs Library
    RPN Query:
    <input type="text" size="30" name="term">
    <input type="submit" name="action" value="Search">
} else {
    echo 'You searced for ' . htmlspecialchars($term) . '<br>';
    for ($i = 0; $i < $num_hosts; $i++) {
        $id[] = yaz_connect($host[$i]);
    for ($i = 0; $i < $num_hosts; $i++) {
        echo '<hr>' . $host[$i] . ":";
        $error = yaz_error($id[$i]);
        if (!empty($error)) {
            echo "Error: $error";
        } else {
            $hits = yaz_hits($id[$i]);
            echo "Result Count $hits";
        echo '<dl>';
        for ($p = 1; $p <= 10; $p++) {
            $rec = yaz_record($id[$i],$p,"string");
            if (empty($rec)) continue;
            echo "<dt><b>$p</b></dt><dd>";
            echo ereg_replace("\n", "<br>\n",$rec);
            echo "</dd>";
        echo '</dl>';

Table of Contents
yaz_addinfo -- Returns additional error information
yaz_ccl_conf -- Configure CCL parser
yaz_ccl_parse -- Invoke CCL Parser
yaz_close -- Closes a YAZ connection
yaz_connect --  Prepares for a connection and Z-association to a Z39.50 target.
yaz_database --  Specifies the databases within a session
yaz_element --  Specifies Element-Set Name for retrieval
yaz_errno -- Returns error number
yaz_error -- Returns error description
yaz_hits -- Returns number of hits for last search
yaz_itemorder --  Prepares for Z39.50 Item Order with an ILL-Request package
yaz_present --  Prepares for retrieval (Z39.50 present).
yaz_range --  Specifies the maximum number of records to retrieve
yaz_record -- Returns a record
yaz_scan_result -- Returns Scan Response result
yaz_scan -- Prepares for a scan
yaz_search -- Prepares for a search
yaz_sort -- Sets sorting criteria
yaz_syntax --  Specifies the preferred record syntax for retrieval.
yaz_wait -- Wait for Z39.50 requests to complete