stream-read.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->

<refentry xml:id="streamwrapper.stream-read" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
 <refnamediv>
  <refname>streamWrapper::stream_read</refname>
  <refpurpose>Read from stream</refpurpose>
 </refnamediv>

 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <modifier>public</modifier> <type class="union"><type>string</type><type>false</type></type><methodname>streamWrapper::stream_read</methodname>
   <methodparam><type>int</type><parameter>count</parameter></methodparam>
  </methodsynopsis>
  <para>
   This method is called in response to <function>fread</function>
   and <function>fgets</function>.
  </para>
  <note>
   <para>
    Remember to update the read/write position of the stream (by the number of
    bytes that were successfully read).
   </para>
  </note>

 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>count</parameter></term>
     <listitem>
      <para>
       How many bytes of data from the current position should be returned.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   If there are less than <parameter>count</parameter>
   bytes available, as many as are available should be returned.
   If no more data is available, an empty string should be returned.
   To signal that reading failed, &false; should be returned.
  </para>
 </refsect1>

 <refsect1 role="errors"><!-- {{{ -->
  &reftitle.errors;
  &userstream.not.implemented.warning;
  <note>
   <para>
    If the return value is longer then <parameter>count</parameter> an
    <constant>E_WARNING</constant> error will be emitted, and excess data will be
    lost.
   </para>
  </note>
 </refsect1><!-- }}} -->
 

<!--
 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>streamWrapper::stream_read</function> example</title>
    <programlisting role="php">
<![CDATA[
<?php
/* ... */
?>
]]>
    </programlisting>
    &example.outputs.similar;
    <screen>
<![CDATA[
...
]]>
    </screen>
   </example>
  </para>
 </refsect1>
-->

 <refsect1 role="notes"><!-- {{{ -->
  &reftitle.notes;
  <note>
   <para>
    <methodname>streamWrapper::stream_eof</methodname> is called directly after
    calling <methodname>streamWrapper::stream_read</methodname> to check if
    <acronym>EOF</acronym> has been reached. If not implemented,
    <acronym>EOF</acronym> is assumed.
   </para>
  </note>
  <warning>
    <para>
      When reading the whole file (for example, with
      <function>file_get_contents</function>), PHP will call
      <methodname>streamWrapper::stream_read</methodname> followed by        
      <methodname>streamWrapper::stream_eof</methodname> in a loop but as long    
      as <methodname>streamWrapper::stream_read</methodname> returns a
      non-empty string, the return value of
      <methodname>streamWrapper::stream_eof</methodname> is ignored.
    </para>
  </warning>
 </refsect1><!-- }}} -->
 
 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>fread</function></member>
    <member><function>fgets</function></member>
   </simplelist>
  </para>
 </refsect1>

</refentry>

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