function.include.html

php的帮助文档,涉及到PHP的案例和基本语法,以及实际应用内容

    </div>
   </p>
   <div class="warning"><b class="warning">Warning</b>
    <h1 class="title">Security warning</h1>
    <p class="para">
     Remote file may be processed at the remote server (depending on the file
     extension and the fact if the remote server runs PHP or not) but it still
     has to produce a valid PHP script because it will be processed at the
     local server. If the file from the remote server should be processed
     there and outputted only, <a href="function.readfile.html" class="function">readfile()</a> is much better
     function to use. Otherwise, special care should be taken to secure the
     remote script to produce a valid and desired code.
    </p>
   </div>
   <p class="para">
    See also <a href="features.remote-files.html" class="link">Remote files</a>,
    <a href="function.fopen.html" class="function">fopen()</a> and <a href="function.file.html" class="function">file()</a> for related
    information.
   </p>
   <p class="simpara">
    Handling Returns: It is possible to execute a <b>return()</b>
    statement inside an included file in order to terminate processing in that
    file and return to the script which called it.  Also, it&#039;s possible to return
    values from included files.  You can take the value of the include call as
    you would a normal function.  This is not, however, possible when including
    remote files unless the output of the remote file has
    <a href="language.basic-syntax.html#language.basic-syntax.phpmode" class="link">valid PHP start
    and end tags</a> (as with any local file).  You can declare the needed
    variables within those tags and they will be introduced at whichever point
    the file was included.
   </p>
   <p class="para">
    Because <b>include()</b> is a special language construct,
    parentheses are not needed around its argument. Take care when comparing
    return value.
    <div class="example">
     <p><b>Example #4 Comparing return value of include</b></p>
     <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #FF8000">//&nbsp;won't&nbsp;work,&nbsp;evaluated&nbsp;as&nbsp;include(('vars.php')&nbsp;==&nbsp;'OK'),&nbsp;i.e.&nbsp;include('')<br /></span><span style="color: #007700">if&nbsp;(include(</span><span style="color: #DD0000">'vars.php'</span><span style="color: #007700">)&nbsp;==&nbsp;</span><span style="color: #DD0000">'OK'</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">'OK'</span><span style="color: #007700">;<br />}<br /><br /></span><span style="color: #FF8000">//&nbsp;works<br /></span><span style="color: #007700">if&nbsp;((include&nbsp;</span><span style="color: #DD0000">'vars.php'</span><span style="color: #007700">)&nbsp;==&nbsp;</span><span style="color: #DD0000">'OK'</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">'OK'</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
     </div>

    </div>
   </p>
   <p class="para">
    <div class="example">
     <p><b>Example #5 <b>include()</b> and the <b>return()</b> statement</b></p>
      <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
return.php<br /><span style="color: #0000BB">&lt;?php<br /><br />$var&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">'PHP'</span><span style="color: #007700">;<br /><br />return&nbsp;</span><span style="color: #0000BB">$var</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">?&gt;<br /></span><br />noreturn.php<br /><span style="color: #0000BB">&lt;?php<br /><br />$var&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">'PHP'</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">?&gt;<br /></span><br />testreturns.php<br /><span style="color: #0000BB">&lt;?php<br /><br />$foo&nbsp;</span><span style="color: #007700">=&nbsp;include&nbsp;</span><span style="color: #DD0000">'return.php'</span><span style="color: #007700">;<br /><br />echo&nbsp;</span><span style="color: #0000BB">$foo</span><span style="color: #007700">;&nbsp;</span><span style="color: #FF8000">//&nbsp;prints&nbsp;'PHP'<br /><br /></span><span style="color: #0000BB">$bar&nbsp;</span><span style="color: #007700">=&nbsp;include&nbsp;</span><span style="color: #DD0000">'noreturn.php'</span><span style="color: #007700">;<br /><br />echo&nbsp;</span><span style="color: #0000BB">$bar</span><span style="color: #007700">;&nbsp;</span><span style="color: #FF8000">//&nbsp;prints&nbsp;1<br /><br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
      </div>

    </div>
   </p>
   <p class="simpara">
    <i>$bar</i> is the value <i>1</i> because the include
    was successful.  Notice the difference between the above examples.  The first uses
    <b>return()</b> within the included file while the other does not.
    If the file can&#039;t be included, <b><tt>FALSE</tt></b> is returned and
    <i>E_WARNING</i> is issued.
   </p>
   <p class="para">
    If there are functions defined in the included file, they can be used in the
    main file independent if they are before <b>return()</b> or after.
    If the file is included twice, PHP 5 issues fatal error because functions
    were already declared, while PHP 4 doesn&#039;t complain about functions
    defined after <b>return()</b>.
    It is recommended to use <b>include_once()</b> instead of
    checking if the file was already included and conditionally return inside
    the included file.
   </p>
   <p class="simpara">
    Another way to &quot;include&quot; a PHP file into a variable is to capture the
    output by using the <a href="ref.outcontrol.html" class="link">Output Control
    Functions</a> with <b>include()</b>. For example:
   </p>
   <p class="para">
    <div class="example">
     <p><b>Example #6 Using output buffering to include a PHP file into a string</b></p>
      <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />$string&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">get_include_contents</span><span style="color: #007700">(</span><span style="color: #DD0000">'somefile.php'</span><span style="color: #007700">);<br /><br />function&nbsp;</span><span style="color: #0000BB">get_include_contents</span><span style="color: #007700">(</span><span style="color: #0000BB">$filename</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;if&nbsp;(</span><span style="color: #0000BB">is_file</span><span style="color: #007700">(</span><span style="color: #0000BB">$filename</span><span style="color: #007700">))&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">ob_start</span><span style="color: #007700">();<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;include&nbsp;</span><span style="color: #0000BB">$filename</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$contents&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">ob_get_contents</span><span style="color: #007700">();<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">ob_end_clean</span><span style="color: #007700">();<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;</span><span style="color: #0000BB">$contents</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;}<br />&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;</span><span style="color: #0000BB">false</span><span style="color: #007700">;<br />}<br /><br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
      </div>

    </div>
   </p>
   <p class="para">
    In order to automatically include files within scripts, see also the
    <a href="ini.core.html#ini.auto-prepend-file" class="link">auto_prepend_file</a> and
    <a href="ini.core.html#ini.auto-append-file" class="link">auto_append_file</a>
    configuration options in <var class="filename">php.ini</var>.
   </p>

   <blockquote><p><b class="note">Note</b>: <span class="simpara">Because this is a 
language construct and not a function, it cannot be called using 
<a href="functions.variable-functions.html" class="link">variable functions</a></span>
</p></blockquote>

   <p class="simpara">
    See also <b>require()</b>, <b>require_once()</b>,
    <b>include_once()</b>, <a href="function.get-included-files.html" class="function">get_included_files()</a>,
    <a href="function.readfile.html" class="function">readfile()</a>, <a href="function.virtual.html" class="function">virtual()</a>, and
    <a href="ini.core.html#ini.include-path" class="link">include_path</a>.
   </p>
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