+ <para>
+ References to temporary records are returned by functions
+ <function>ZOOM_resultset_records</function> or
+ <function>ZOOM_resultset_record</function>.
+ </para>
+ <para>
+ If a persistent reference to a record is desired
+ <function>ZOOM_record_clone</function> should be used.
+ It returns a record reference that should be destroyed
+ by a call to <function>ZOOM_record_destroy</function>.
+ </para>
+ <para>
+ A single record is returned by function
+ <function>ZOOM_resultset_record</function> that takes a
+ position as argument. First record has position zero.
+ If no record could be obtained <literal>NULL</literal> is returned.
+ </para>
+ <para>
+ Function <function>ZOOM_resultset_records</function> retrieves
+ a number of records from a result set. Parameter <literal>start</literal>
+ and <literal>count</literal> specifies the range of records to
+ be returned. Upon completion array
+ <literal>recs[0], ..recs[count-1]</literal>
+ holds record objects for the records. The array of records
+ <literal>recs</literal> should be allocated prior the call
+ <function>ZOOM_resultset_records</function>. Note that for those
+ records that couldn't be retrieved from the target
+ <literal>recs[ ..]</literal> is set to <literal>NULL</literal>.
+ </para>
+ <para id="zoom.record.get">
+ In order to extract information about a single record,
+ <function>ZOOM_record_get</function> is provided. The
+ function returns a pointer to certain record information. The
+ nature (type) of the pointer depends on the parameter,
+ <parameter>type</parameter>.
+ </para>
+ <para>
+ The <parameter>type</parameter> is a string of the format:
+ </para>
+ <para>
+ <replaceable>form</replaceable>[; charset=<replaceable>from</replaceable>[,<replaceable>to</replaceable>]]
+ </para>
+ <para>
+ where <replaceable>form</replaceable> specifies the format of the
+ returned record, <replaceable>from</replaceable>
+ specifies the character set of the record in its original form
+ (as returned by the server), <replaceable>to</replaceable> specifies
+ the output (returned)
+ character set encoding.
+ If charset is not given, then no character set conversion takes place.
+ If <replaceable>to</replaceable> is omitted UTF-8 is assumed.
+ </para>
+ <para>
+ In addition, for certain types, the length
+ <literal>len</literal> passed will be set to the size in bytes of
+ the returned information.
+ </para>
+ <para>
+ The following are the supported values for <replaceable>form</replaceable>.
+ <variablelist>
+ <varlistentry><term><literal>database</literal></term>
+ <listitem><para>Database of record is returned
+ as a C null-terminated string. Return type
+ <literal>const char *</literal>.
+ </para></listitem>
+ </varlistentry>
+ <varlistentry><term><literal>syntax</literal></term>
+ <listitem><para>The transfer syntax of the record is returned
+ as a C null-terminated string containing the symbolic name of
+ the record syntax, e.g. <literal>Usmarc</literal>. Return type
+ is
+ <literal>const char *</literal>.
+ </para></listitem>
+ </varlistentry>
+ <varlistentry><term><literal>render</literal></term>
+ <listitem><para>The record is returned in a display friendly
+ format. Upon completion buffer is returned
+ (type <literal>const char *</literal>) and length is stored in
+ <literal>*len</literal>.
+ </para></listitem>
+ </varlistentry>
+ <varlistentry><term><literal>raw</literal></term>
+ <listitem><para>The record is returned in the internal
+ YAZ specific format. For GRS-1, Explain, and others, the
+ raw data is returned as type
+ <literal>Z_External *</literal> which is just the type for
+ the member <literal>retrievalRecord</literal> in
+ type <literal>NamePlusRecord</literal>.
+ For SUTRS and octet aligned record (including all MARCs) the
+ octet buffer is returned and the length of the buffer.
+ </para></listitem>
+ </varlistentry>
+ <varlistentry><term><literal>xml</literal></term>
+ <listitem><para>The record is returned in XML if possible.
+ SRW/SRU and Z39.50 records with transfer syntax XML are
+ returned verbatim. MARC records are returned in
+ <ulink url="http://www.loc.gov/standards/marcxml/">
+ MARCXML
+ </ulink>
+ (converted from ISO2709 to MARCXML by YAZ).
+ GRS-1 and OPAC records are not supported for this form.
+ Upon completion, the XML buffer is returned
+ (type <literal>const char *</literal>) and length is stored in
+ <literal>*len</literal>.
+ </para></listitem>
+ </varlistentry>
+ <varlistentry><term><literal>opac</literal></term>
+ <listitem><para>OPAC for record is returned in XML.
+ </para></listitem>
+ </varlistentry>
+ </variablelist>
+ </para>
+ <para>
+ Most
+ <ulink url="http://www.loc.gov/marc/">
+ MARC21
+ </ulink>
+ records uses the
+ <ulink url="http://www.loc.gov/marc/specifications/speccharmarc8.html">
+ MARC-8
+ </ulink>
+ character set encoding.
+ An application that wishes to display in Latin-1 would use
+ <screen>
+ render; charset=marc8,iso-8859-1
+ </screen>
+ </para>
+ <sect2><title>Z39.50 Protocol behavior</title>
+ <para>
+ The functions <function>ZOOM_resultset_record</function> and
+ <function>ZOOM_resultset_records</function> inspects the client-side
+ record cache. Records not found in cache are fetched using
+ Present.
+ The functions may block (and perform network I/O) - even though option
+ <literal>async</literal> is 1, because they return records objects.
+ (and there's no way to return records objects without retrieving them!).
+ </para>
+ <para>
+ There is a trick, however, in the usage of function
+ <function>ZOOM_resultset_records</function> that allows for
+ delayed retrieval (and makes it non-blocking). By using
+ a null pointer for <parameter>recs</parameter> you're indicating
+ you're not interested in getting records objects
+ <emphasis>now</emphasis>.
+ </para>
+ </sect2>
+ <sect2><title>SRW Protocol behavior</title>
+ <para>
+ The ZOOM driver for SRW treats records returned by a SRW server
+ as if they where Z39.50 records with transfer syntax XML and
+ no element set name or database name.
+ </para>
+ </sect2>