php-doc-en/functions/filesystem.xml

<?xml encoding="iso-8859-1"?>
<!-- $Revision: 1.81 $ -->
 <reference id="ref.filesystem">
  <title>Filesystem functions</title>
  <titleabbrev>Filesystem</titleabbrev>

  <refentry id="function.basename">
   <refnamediv>
    <refname>basename</refname>
    <refpurpose>
     Returns filename component of path
    </refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>string <function>basename</function></funcdef>
      <paramdef>string <parameter>path</parameter></paramdef>
      <paramdef>string <parameter><optional>suffix</optional></parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Given a string containing a path to a file, this function will
     return the base name of the file.
     If the filename ends in <parameter>suffix</parameter> this will
     also be cut off (the <parameter>suffix</parameter> parameter was added 
     in PHP 4.0.7).
    </para>
    <para>
     On Windows, both slash (<literal>/</literal>) and backslash
     (<literal>\</literal>) are used as path separator character.  In
     other environments, it is the forward slash
     (<literal>/</literal>).
    </para>
    <para>
     <example>
      <title><function>basename</function> example</title>
      <programlisting role="php">
$path = "/home/httpd/html/index.php3";
$file = basename ($path); // $file is set to "index.php3"
$file = basename ($path,".php3"); // $file is set to "index"
      </programlisting>
     </example>
    </para>
    <para>
     See also: <function>dirname</function>
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.chgrp">
   <refnamediv>
    <refname>chgrp</refname>
    <refpurpose>Changes file group</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>chgrp</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
      <paramdef>mixed <parameter>group</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Attempts to change the group of the file
     <parameter>filename</parameter> to
     <parameter>group</parameter>. Only the superuser may change the
     group of a file arbitrarily; other users may change the group of
     a file to any group of which that user is a member.
    </para>
    <para>
     Returns &true; on success; otherwise returns &false;.
    </para>
    <para>
     See also <function>chown</function> and
     <function>chmod</function>.
    </para>
    <note>
     <simpara>
      This function does not work on Windows systems
     </simpara>
    </note>
   </refsect1>
  </refentry>

  <refentry id="function.chmod">
   <refnamediv>
    <refname>chmod</refname>
    <refpurpose>Changes file mode</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>chmod</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
      <paramdef>int <parameter>mode</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Attempts to change the mode of the file specified by
     <parameter>filename</parameter> to that given in
     <parameter>mode</parameter>.
    </para>
    <para>
     Note that <parameter>mode</parameter> is not automatically
     assumed to be an octal value, so strings (such as "g+w") will
     not work properly. To ensure the expected operation,
     you need to prefix <parameter>mode</parameter> with a zero (0):
     <informalexample>
      <programlisting role="php">
chmod ("/somedir/somefile", 755);   // decimal; probably incorrect   
chmod ("/somedir/somefile", "u+rwx,go+rx"); // string; incorrect       
chmod ("/somedir/somefile", 0755);  // octal; correct value of mode
      </programlisting>
     </informalexample>
    </para>
    <para>
     Returns &true; on success and &false; otherwise.
    </para>
    <para>
     See also <function>chown</function> and
     <function>chgrp</function>.
    </para>
    <note>
     <simpara>
      This function does not work on Windows systems
     </simpara>
    </note>
   </refsect1>
  </refentry>

  <refentry id="function.chown">
   <refnamediv>
    <refname>chown</refname>
    <refpurpose>Changes file owner</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>chown</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
      <paramdef>mixed <parameter>user</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Attempts to change the owner of the file filename to user
     user. Only the superuser may change the owner of a file.
    </para>
    <para>
     Returns &true; on success; otherwise returns &false;.
    </para>
    <para>
     See also <function>chown</function> and
     <function>chmod</function>.
    </para>
    <note>
     <simpara>
     This function does not work on Windows systems
     </simpara>
    </note>
   </refsect1>
  </refentry>

  <refentry id="function.clearstatcache">
   <refnamediv>
    <refname>clearstatcache</refname>
    <refpurpose>Clears file stat cache</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>void <function>clearstatcache</function></funcdef>
      <void/>
     </funcprototype>
    </funcsynopsis>
    <para>
     Invoking the <systemitem>stat</systemitem> or
     <systemitem>lstat</systemitem> system call on most systems is
     quite expensive. Therefore, the result of the last call to any of
     the status functions (listed below) is stored for use on the next
     such call using the same filename. If you wish to force a new
     status check, for instance if the file is being checked many
     times and may change or disappear, use this function to clear the
     results of the last call from memory.
    </para>
    <para>
     This value is only cached for the lifetime of a single request.
    </para>
    <para>
     Affected functions include <function>stat</function>,
     <function>lstat</function>,
     <function>file_exists</function>,
     <function>is_writable</function>,
     <function>is_readable</function>,
     <function>is_executable</function>,
     <function>is_file</function>,
     <function>is_dir</function>,
     <function>is_link</function>,
     <function>filectime</function>,
     <function>fileatime</function>,
     <function>filemtime</function>,
     <function>fileinode</function>,
     <function>filegroup</function>,
     <function>fileowner</function>,
     <function>filesize</function>,
     <function>filetype</function>, and
     <function>fileperms</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.copy">
   <refnamediv>
    <refname>copy</refname>
    <refpurpose>Copies file</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>copy</function></funcdef>
      <paramdef>string <parameter>source</parameter></paramdef>
      <paramdef>string <parameter>dest</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Makes a copy of a file.  Returns &true; if the copy succeeded,
     &false; otherwise.
     <example>
      <title><function>copy</function> example</title>
      <programlisting role="php">
if (!copy($file, $file.'.bak')) {
    print ("failed to copy $file...&lt;br>\n");
}
      </programlisting>
     </example>
    </para>
    <para>
     See also: <function>rename</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.delete">
   <refnamediv>
    <refname>delete</refname>
    <refpurpose>A dummy manual entry</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>void <function>delete</function></funcdef>
      <paramdef>string <parameter>file</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     This is a dummy manual entry to satisfy those people who are
     looking for <function>unlink</function> or
     <function>unset</function> in the wrong place.
    </para>
    <para>
     See also: <function>unlink</function> to delete files,
     <function>unset</function> to delete variables.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.dirname">
   <refnamediv>
    <refname>dirname</refname>
    <refpurpose>Returns directory name component of path</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>string <function>dirname</function></funcdef>
      <paramdef>string <parameter>path</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Given a string containing a path to a file, this function will
     return the name of the directory.</para>
    <para>
     On Windows, both slash (<literal>/</literal>) and backslash
     (<literal>\</literal>) are used as path separator character.  In
     other environments, it is the forward slash
     (<literal>/</literal>).</para>
    <para>
     <example>
      <title><function>dirname</function> example</title>
      <programlisting role="php">
$path = "/etc/passwd";
$file = dirname ($path); // $file is set to "/etc"
      </programlisting>
     </example>
    </para>
    <para>
     See also: <function>basename</function>
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.diskfreespace">
   <refnamediv>
    <refname>diskfreespace</refname>
    <refpurpose>Returns available space in directory</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>float <function>diskfreespace</function></funcdef>
      <paramdef>string <parameter>directory</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Given a string containing a directory, this function will return
     the number of bytes available on the corresponding filesystem or
     disk partition.
    </para>
    <para>
     <example>
      <title><function>diskfreespace</function> example</title>
      <programlisting role="php">
$df = diskfreespace("/"); // $df contains the number of bytes 
                          // available on "/"
      </programlisting>
     </example>
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.disk-total-space">
   <refnamediv>
    <refname>disk_total_space</refname>
    <refpurpose>Returns the total size of a directory</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>float <function>disk_total_space</function></funcdef>
      <paramdef>string <parameter>directory</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Given a string containing a directory, this function will return
     the total number of bytes on the corresponding filesystem or disk
     partition.
    </para>
    <para>
     <example>
      <title><function>disk_total_space</function> example</title>
      <programlisting role="php">
$df = disk_total_space("/"); // $df contains the total number of
                             // bytes available on "/"
      </programlisting>
     </example>
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.fclose">
   <refnamediv>
    <refname>fclose</refname>
    <refpurpose>Closes an open file pointer</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>fclose</function></funcdef>
      <paramdef>int <parameter>fp</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     The file pointed to by <parameter>fp</parameter> is closed.
    </para>
    <para>
     Returns &true; on success and &false;
     on failure.
    </para>
    <para>
     The file pointer must be valid, and must point to a file
     successfully opened by <function>fopen</function> or
     <function>fsockopen</function>.
    </para> 
   </refsect1>
  </refentry>

  <refentry id="function.feof">
   <refnamediv>
    <refname>feof</refname>
    <refpurpose>Tests for end-of-file on a file pointer</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>feof</function></funcdef>
      <paramdef>int <parameter>fp</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Returns &true; if the file pointer is at EOF or an error occurs;
     otherwise returns &false;.
    </para>
    <para>
     The file pointer must be valid, and must point to a file
     successfully opened by <function>fopen</function>,
     <function>popen</function>, or <function>fsockopen</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.fflush">
   <refnamediv>
    <refname>fflush</refname>
    <refpurpose>Flushes the output to a file</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>fflush</function></funcdef>
      <paramdef>int <parameter>fp</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     This function forces a write of all buffered output to the 
     to the resource pointed to by the file handle 
     <parameter>fp</parameter>. Returns &true; if succesful, &false;
     otherwise.
    </para>
    <para>
     The file pointer must be valid, and must point to a file
     successfully opened by <function>fopen</function>,
     <function>popen</function>, or <function>fsockopen</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.fgetc">
   <refnamediv>
    <refname>fgetc</refname>
    <refpurpose>Gets character from file pointer</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>string <function>fgetc</function></funcdef>
      <paramdef>int <parameter>fp</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Returns a string containing a single character read from the
     file pointed to by fp.  Returns &false; on EOF.
    </para>
    <para>
     The file pointer must be valid, and must point to a file
     successfully opened by <function>fopen</function>,
     <function>popen</function>, or <function>fsockopen</function>.
    </para>
    <para> 
     See also <function>fread</function>, <function>fopen</function>,
     <function>popen</function>, <function>fsockopen</function>, and
     <function>fgets</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.fgetcsv">
   <refnamediv>
    <refname>fgetcsv</refname>
    <refpurpose>
     Gets line from file pointer and parse for CSV fields
    </refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>array <function>fgetcsv</function></funcdef>
      <paramdef>int <parameter>fp</parameter></paramdef>
      <paramdef>int <parameter>length</parameter></paramdef>
      <paramdef>string 
       <parameter>
        <optional>delimiter</optional>
       </parameter>
      </paramdef>
     </funcprototype>
    </funcsynopsis>
    <simpara>
     Similar to <function>fgets</function> except that
     <function>fgetcsv</function> parses the line it reads for fields
     in <acronym>CSV</acronym> format and returns an array containing
     the fields read.  The field delimiter is a comma, unless you
     specify another delimiter with the optional third parameter.
    </simpara>
    <simpara>
     <parameter>Fp</parameter> must be a valid file pointer to a file
     successfully opened by <function>fopen</function>,
     <function>popen</function>, or <function>fsockopen</function>
    </simpara>
    <simpara>
     Length must be greater than the longest line to be found in the
     CSV file (allowing for trailing line-end characters).
    </simpara>
    <simpara>
     <function>fgetcsv</function> returns &false; on error, including
     end of file.
    </simpara>
    <simpara>
     N.B. A blank line in a CSV file will be returned as an array
     comprising a single &null; field, and will not be treated as an
     error.
    </simpara>
    <example>
     <title>
      <function>fgetcsv</function> example - Read and print entire
      contents of a CSV file
     </title>
     <programlisting role="php">
$row = 1;
$fp = fopen ("test.csv","r");
while ($data = fgetcsv ($fp, 1000, ",")) {
    $num = count ($data);
    print "&lt;p&gt; $num fields in line $row: &lt;br&gt;";
    $row++;
    for ($c=0; $c&lt;$num; $c++) {
        print $data[$c] . "&lt;br&gt;";
    }
}
fclose ($fp);
     </programlisting>
    </example>
   </refsect1>
  </refentry>

  <refentry id="function.fgets">
   <refnamediv>
    <refname>fgets</refname>
    <refpurpose>Gets line from file pointer</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>string <function>fgets</function></funcdef>
      <paramdef>int <parameter>fp</parameter></paramdef>
      <paramdef>int <parameter>length</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Returns a string of up to length - 1 bytes read from the file
     pointed to by fp. Reading ends when length - 1 bytes have been
     read, on a newline (which is included in the return value), or on
     EOF (whichever comes first).
    </para>
    <para>
     If an error occurs, returns &false;.
    </para>
    <para>
     Common Pitfalls:
    </para>
    <simpara>
     People used to the 'C' semantics of fgets should note the
     difference in how EOF is returned.
    </simpara>
    <simpara>
     The file pointer must be valid, and must point to a file
     successfully opened by <function>fopen</function>,
     <function>popen</function>, or
     <function>fsockopen</function>.
    </simpara>
    <para>
     A simple example follows:
     <example> 
      <title>Reading a file line by line</title>
      <programlisting role="php">
$fd = fopen ("/tmp/inputfile.txt", "r");
while (!feof ($fd)) {
    $buffer = fgets($fd, 4096);
    echo $buffer;
}
fclose ($fd);
      </programlisting>
     </example>
    </para>
    <para> 
     See also <function>fread</function>, <function>fopen</function>,
     <function>popen</function>, <function>fgetc</function>,
     <function>fsockopen</function>, and
     <function>socket_set_timeout</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.fgetss">
   <refnamediv>
    <refname>fgetss</refname>
    <refpurpose>
     Gets line from file pointer and strip HTML tags
    </refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>string <function>fgetss</function></funcdef>
      <paramdef>int <parameter>fp</parameter></paramdef>
      <paramdef>int <parameter>length</parameter></paramdef>
      <paramdef>string 
       <parameter>
        <optional>allowable_tags</optional>
       </parameter>
      </paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Identical to <function>fgets</function>, except that fgetss
     attempts to strip any HTML and PHP tags from the text it
     reads.
    </para>
    <para>
     You can use the optional third parameter to specify tags which
     should not be stripped.
     <note>
      <para>
       <parameter>allowable_tags</parameter> was added in PHP 3.0.13,
       PHP4B3.
      </para> 
     </note>
    </para>
    <para>
     See also <function>fgets</function>, <function>fopen</function>,
     <function>fsockopen</function>, <function>popen</function>, and
     <function>strip_tags</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.file">
   <refnamediv>
    <refname>file</refname> 
    <refpurpose>Reads entire file into an array</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>array <function>file</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
      <paramdef>int 
       <parameter><optional>use_include_path</optional></parameter>
      </paramdef>
     </funcprototype>
    </funcsynopsis>
    <para> 
     Identical to <function>readfile</function>, except that
     <function>file</function> returns the file in an array. Each
     element of the array corresponds to a line in the file, with the
     newline still attached.
    </para>
    <para>
     You can use the optional second parameter and set it to "1", if
     you want to search for the file in the <link
     linkend="ini.include-path">include_path</link>, too.
    </para>
    <para>
     <informalexample>
      <programlisting role="php">
&lt;?php
// get a web page into an array and print it out
$fcontents = file ('http://www.php.net');
while (list ($line_num, $line) = each ($fcontents)) {
    echo "&lt;b&gt;Line $line_num:&lt;/b&gt; " . htmlspecialchars ($line) . "&lt;br&gt;\n";
}

// get a web page into a string
$fcontents = join ('', file ('http://www.php.net'));
?&gt;
      </programlisting>
     </informalexample>
    </para>
    <para> 
     See also <function>readfile</function>,
     <function>fopen</function>, <function>fsockopen</function>, and
     <function>popen</function>.
    </para>
   </refsect1>
  </refentry>


  <refentry id="function.file-exists">
   <refnamediv>
    <refname>file_exists</refname>
    <refpurpose>Checks whether a file exists</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>file_exists</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <simpara>
     Returns &true; if the file specified by
     <parameter>filename</parameter> exists; &false; otherwise.
    </simpara>
    <simpara>
     This function will not work on <link
     linkend="features.remote-files">remote files</link>; the file to
     be examined must be accessible via the server's filesystem.
    </simpara>
    <simpara>
     The results of this function are cached. See
     <function>clearstatcache</function> for more details.
    </simpara>
   </refsect1>
  </refentry>


  <refentry id="function.fileatime">
   <refnamediv>
    <refname>fileatime</refname>
    <refpurpose>Gets last access time of file</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>fileatime</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <simpara> 
     Returns the time the file was last accessed, or &false; in case of
     an error. The time is returned as a Unix timestamp.
    </simpara>
    <simpara>
     The results of this function are cached. See
     <function>clearstatcache</function> for more details.
    </simpara>
    <simpara>
     Note: The atime of a file is supposed to change whenever
     the data blocks of a file are being read. This can be
     costly performancewise when an application regularly
     accesses a very large number of files or directories. Some
     Unix filesystems can be mounted with atime updates disabled
     to increase the performance of such applications; USENET
     news spools are a common example. On such filesystems
     this function will be useless.
    </simpara>
    <simpara>
     This function will not work on <link
     linkend="features.remote-files">remote files</link>; the file to
     be examined must be accessible via the server's filesystem.
    </simpara>
   </refsect1>
  </refentry>

  <refentry id="function.filectime">
   <refnamediv>
    <refname>filectime</refname>
    <refpurpose>Gets inode change time of file</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>filectime</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Returns the time the file was last changed, or &false; in case of
     an error. The time is returned as a Unix timestamp.
    </para>
    <para>
     The results of this function are cached. See
     <function>clearstatcache</function> for more details.
    </para>
    <para>
     Note: In most Unix filesystems, a file is considered
     changed when its inode data is changed; that is, when
     the permissions, owner, group, or other metadata
     from the inode is updated. See also 
     <function>filemtime</function> (which is what you want to use
     when you want to create "Last Modified" footers on web pages) and 
     <function>fileatime</function>.
    </para>
    <para>Note also that in some Unix texts the ctime of a file is
     referred to as being the creation time of the file. This is wrong.
     There is no creation time for Unix files in most Unix filesystems.
    </para>
    <simpara>
     This function will not work on <link
     linkend="features.remote-files">remote files</link>; the file to
     be examined must be accessible via the server's filesystem.
    </simpara>
   </refsect1>
  </refentry>

  <refentry id="function.filegroup">
   <refnamediv>
    <refname>filegroup</refname>
    <refpurpose>Gets file group</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>filegroup</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>    
     Returns the group ID of the owner of the file, or &false; in case
     of an error. The group ID is returned in numerical format, use
     <function>posix_getgrgid</function> to resolve it to a group name.
    </para>
    <para>
     The results of this function are cached. See
     <function>clearstatcache</function> for more details.
    </para>
    <note>
     <simpara>
     This function does not work on Windows systems
     </simpara>
    <simpara>
     This function will not work on <link
     linkend="features.remote-files">remote files</link>; the file to
     be examined must be accessible via the server's filesystem.
    </simpara>
    </note>
   </refsect1>
  </refentry>

  <refentry id="function.fileinode">
   <refnamediv>
    <refname>fileinode</refname>
    <refpurpose>Gets file inode</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>fileinode</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para> 
     Returns the inode number of the file, or &false; in case of an
     error.</para>
    <para>
     The results of this function are cached. See
     <function>clearstatcache</function> for more details.
    </para>
    <simpara>
     This function will not work on <link
     linkend="features.remote-files">remote files</link>; the file to
     be examined must be accessible via the server's filesystem.
    </simpara>
    <note>
     <simpara>
     This function does not work on Windows systems
     </simpara>
    </note>
   </refsect1>
  </refentry>

  <refentry id="function.filemtime">
   <refnamediv>
    <refname>filemtime</refname>
    <refpurpose>Gets file modification time</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>filemtime</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Returns the time the file was last modified, or &false; in case of
     an error. The time is returned as a Unix timestamp.
    </para>
    <para>
     The results of this function are cached. See
     <function>clearstatcache</function> for more details.
    </para>
    <simpara>
     This function will not work on <link
     linkend="features.remote-files">remote files</link>; the file to
     be examined must be accessible via the server's filesystem.
    </simpara>
    <para>Note: This function returns the time when the data
     blocks of a file were being written to, that is, the time
     when the content of the file was changed. Use
     <function>date</function> on the result of this function
     to get a printable modification date for use in page footers.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.fileowner">
   <refnamediv>
    <refname>fileowner</refname>
    <refpurpose>Gets file owner</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>fileowner</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>    
     Returns the user ID of the owner of the file, or &false; in case of
     an error. The user ID is returned in numerical format, use
     <function>posix_getpwuid</function> to resolve it to a username.
    </para>
    <para>
     The results of this function are cached. See
     <function>clearstatcache</function> for more details.
    </para>
    <simpara>
     This function will not work on <link
     linkend="features.remote-files">remote files</link>; the file to
     be examined must be accessible via the server's filesystem.
    </simpara>
    <note>
     <simpara>
     This function does not work on Windows systems
     </simpara>
    </note>
   </refsect1>
  </refentry>

  <refentry id="function.fileperms">
   <refnamediv>
    <refname>fileperms</refname>
    <refpurpose>Gets file permissions</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>fileperms</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>    
     Returns the permissions on the file, or &false; in case of an error.
    </para>
    <simpara>
     This function will not work on <link
     linkend="features.remote-files">remote files</link>; the file to
     be examined must be accessible via the server's filesystem.
    </simpara>
    <para>
     The results of this function are cached. See
     <function>clearstatcache</function> for more details.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.filesize">
   <refnamediv>
    <refname>filesize</refname>
    <refpurpose>Gets file size</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>filesize</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para> 
     Returns the size of the file, or &false; in case of an error.
    </para>
    <para>
     The results of this function are cached. See
     <function>clearstatcache</function> for more details.
    </para>
    <simpara>
     This function will not work on <link
     linkend="features.remote-files">remote files</link>; the file to
     be examined must be accessible via the server's filesystem.
    </simpara>
   </refsect1>
  </refentry>

  <refentry id="function.filetype">
   <refnamediv>
    <refname>filetype</refname>
    <refpurpose>Gets file type</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>string <function>filetype</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>    
     Returns the type of the file. Possible values are fifo, char,
     dir, block, link, file, and unknown.</para> <para> Returns &false;
     if an error occurs.
    </para>
    <para>
     The results of this function are cached. See
     <function>clearstatcache</function> for more details.
    </para>
    <simpara>
     This function will not work on <link
     linkend="features.remote-files">remote files</link>; the file to
     be examined must be accessible via the server's filesystem.
    </simpara>
   </refsect1>
  </refentry>

  <refentry id="function.flock">
   <refnamediv>
    <refname>flock</refname>
    <refpurpose>Portable advisory file locking</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>flock</function></funcdef>
      <paramdef>int <parameter>fp</parameter></paramdef>
      <paramdef>int <parameter>operation</parameter></paramdef>
      <paramdef>int 
       <parameter>
        <optional>wouldblock</optional>
       </parameter>
      </paramdef>
     </funcprototype>
    </funcsynopsis>
    <simpara>
     PHP supports a portable way of locking complete files in an
     advisory way (which means all accessing programs have to use the
     same way of locking or it will not work).
    </simpara>
    <simpara>
     <function>flock</function> operates on <parameter>fp</parameter>
     which must be an open file
     pointer. <parameter>operation</parameter> is one of the following
     values:
    </simpara>
    <para>
     <itemizedlist>
      <listitem>
       <simpara>
         To acquire a shared lock (reader), set
         <parameter>operation</parameter> to LOCK_SH (set to 1 prior to
         PHP 4.0.1).
       </simpara>
      </listitem>
      <listitem>
       <simpara>
         To acquire an exclusive lock (writer), set
         <parameter>operation</parameter> to LOCK_EX (set to 2 prior to
         PHP 4.0.1).
       </simpara>
      </listitem>
      <listitem>
       <simpara>
         To release a lock (shared or exclusive), set
         <parameter>operation</parameter> to LOCK_UN (set to 3 prior to
         PHP 4.0.1).
       </simpara>
      </listitem>
      <listitem>
       <simpara>
         If you don't want <function>flock</function> to block while
         locking, add LOCK_NB (4 prior to PHP 4.0.1) to
         <parameter>operation</parameter>.
       </simpara>
      </listitem>
     </itemizedlist>
    </para>
    <simpara>
     <function>flock</function> allows you to perform a simple
     reader/writer model which can be used on virtually every platform
     (including most Unices and even Windows).  The optional 3rd
     argument is set to &true; if the lock would block (EWOULDBLOCK
     errno condition)
    </simpara>
    <simpara>
     <function>flock</function> returns &true; on success and &false; on
     error (e.g. when a lock could not be acquired).
    </simpara>
    <warning>
     <para>
      On most operation systems <function>flock</function> is implemented
      at the process level. When using a multithreaded server API like
      ISAPI you cannot rely on <function>flock</function> to protect
      files against other PHP scripts running in parallel threads of the
      same server instance!
     </para>
    </warning>
   </refsect1>
  </refentry>

  <refentry id="function.fopen">
   <refnamediv>
    <refname>fopen</refname>
    <refpurpose>Opens file or URL</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>fopen</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
      <paramdef>string <parameter>mode</parameter></paramdef>
      <paramdef>int 
       <parameter>
        <optional>use_include_path</optional>
       </parameter>
      </paramdef>
     </funcprototype>
    </funcsynopsis>
    <simpara>
     If <parameter>filename</parameter> begins with "http://" (not
     case sensitive), an HTTP 1.0 connection is opened to the
     specified server, the page is requested using the HTTP GET
     method, and a file pointer is returned to the beginning
     of the body of the response. A 'Host:' header is sent with the
     request in order to handle name-based virtual hosts.
    </simpara>
    <simpara>
     Note that the file pointer allows you to retrieve only the
     <emphasis>body</emphasis> of the response; you cannot
     access the HTTP response header using this function.
    </simpara>
    <simpara>
     Versions prior to PHP 4.0.5 do not handle HTTP redirects. Because
     of this, directories must include trailing slashes.
    </simpara>
    <simpara>
     If <parameter>filename</parameter> begins with "ftp://" (not case
     sensitive), an ftp connection to the specified server is opened
     and a pointer to the requested file is returned. If the server
     does not support passive mode ftp, this will fail. You can open
     files for either reading or writing via ftp (but not both
     simultaneously).
    </simpara>
    <simpara>
     If <parameter>filename</parameter> is one of "php://stdin",
     "php://stdout", or "php://stderr", the corresponding stdio
     stream will be opened.  (This was introduced in PHP 3.0.13;
     in earlier versions, a filename such as "/dev/stdin" or
     "/dev/fd/0" must be used to access the stdio streams.)
    </simpara>
    <simpara>
     If <parameter>filename</parameter> begins with anything else, the
     file will be opened from the filesystem, and a file pointer to
     the file opened is returned.
    </simpara>
    <simpara>
     If the open fails, the function returns &false;.
    </simpara>
    <para>
     <parameter>mode</parameter> may be any of the following:
     <itemizedlist>
      <listitem>
       <simpara>
        'r' - Open for reading only; place the file pointer at the
        beginning of the file.
       </simpara>
      </listitem>
      <listitem>
       <simpara>
        'r+' - Open for reading and writing; place the file pointer at
        the beginning of the file.
       </simpara>
      </listitem>
      <listitem>
       <simpara>
        'w' - Open for writing only; place the file pointer at the
        beginning of the file and truncate the file to zero length.
        If the file does not exist, attempt to create it.
       </simpara>
      </listitem>
      <listitem>
       <simpara>
        'w+' - Open for reading and writing; place the file pointer at
        the beginning of the file and truncate the file to zero
        length.  If the file does not exist, attempt to create it.
       </simpara>
      </listitem>
      <listitem>
       <simpara>
        'a' - Open for writing only; place the file pointer at the end
        of the file. If the file does not exist, attempt to create
        it.
       </simpara>
      </listitem>
      <listitem>
       <simpara>
        'a+' - Open for reading and writing; place the file pointer at
        the end of the file. If the file does not exist, attempt to
        create it.
       </simpara>
      </listitem>
     </itemizedlist>
    </para>
    <note>
     <para>
      The <parameter>mode</parameter> may contain the letter
      'b'. This is useful only on systems which differentiate between
      binary and text files (i.e. Windows. It's useless on Unix). 
      If not needed, this will be ignored.
     </para>
    </note>
    <para>
     You can use the optional third parameter and set it to "1", if
     you want to search for the file in the <link
     linkend="ini.include-path">include_path</link>, too.
    </para>
    <para>
     <example>
      <title><function>fopen</function> example</title>
      <programlisting role="php">
$fp = fopen ("/home/rasmus/file.txt", "r");
$fp = fopen ("/home/rasmus/file.gif", "wb");
$fp = fopen ("http://www.php.net/", "r");
$fp = fopen ("ftp://user:password@example.com/", "w");
      </programlisting>
     </example>
    </para>
    <simpara>
     If you are experiencing problems with reading and writing to
     files and you're using the server module version of PHP, remember
     to make sure that the files and directories you're using are
     accessible to the server process.
    </simpara>
    <para>
     On the Windows platform, be careful to escape any backslashes
     used in the path to the file, or use forward slashes.
     <informalexample>
      <programlisting role="php"> 
$fp = fopen ("c:\\data\\info.txt", "r");
      </programlisting>
     </informalexample>
    </para>
    <simpara>
     See also <function>fclose</function>,
     <function>fsockopen</function>,
     <function>socket_set_timeout</function>, and
     <function>popen</function>.
    </simpara>
   </refsect1>
  </refentry>

  <refentry id="function.fpassthru">
   <refnamediv>
    <refname>fpassthru</refname> 
    <refpurpose>
     Output all remaining data on a file pointer
    </refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>fpassthru</function></funcdef>
      <paramdef>int <parameter>fp</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <simpara>
     Reads to EOF on the given file pointer and writes the results to
     standard output.
    </simpara>
    <simpara>
     If an error occurs, <function>fpassthru</function> returns
     &false;.
    </simpara>
    <simpara>
     The file pointer must be valid, and must point to a file
     successfully opened by <function>fopen</function>,
     <function>popen</function>, or <function>fsockopen</function>.
     The file is closed when <function>fpassthru</function> is done
     reading it (leaving <parameter>fp</parameter> useless).
    </simpara>
    <simpara>
     If you just want to dump the contents of a file to stdout you may
     want to use the <function>readfile</function>, which saves you
     the <function>fopen</function> call.
    </simpara>
    <simpara>
     See also <function>readfile</function>,
     <function>fopen</function>, <function>popen</function>, and
     <function>fsockopen</function>
    </simpara>
   </refsect1>
  </refentry>

  <refentry id="function.fputs">
   <refnamediv>
    <refname>fputs</refname>
    <refpurpose>Writes to a file pointer</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>fputs</function></funcdef>
      <paramdef>int <parameter>fp</parameter></paramdef>
      <paramdef>string <parameter>str</parameter></paramdef>
      <paramdef>int 
       <parameter>
        <optional>length</optional>
       </parameter>
      </paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     <function>fputs</function> is an alias to
     <function>fwrite</function>, and is identical in every way.  Note
     that the <parameter>length</parameter> parameter is optional and
     if not specified the entire string will be written.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.fread">
   <refnamediv>
    <refname>fread</refname>
    <refpurpose>Binary-safe file read</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>string <function>fread</function></funcdef>
      <paramdef>int <parameter>fp</parameter></paramdef>
      <paramdef>int <parameter>length</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <simpara>
     <function>fread</function> reads up to
     <parameter>length</parameter> bytes from the file pointer
     referenced by <parameter>fp</parameter>. Reading stops when
     <parameter>length</parameter> bytes have been read or EOF is
     reached, whichever comes first.
    </simpara> 
    <para>
     <informalexample>
      <programlisting role="php">
// get contents of a file into a string
$filename = "/usr/local/something.txt";
$fd = fopen ($filename, "r");
$contents = fread ($fd, filesize ($filename));
fclose ($fd);
      </programlisting>
     </informalexample>
    </para>
    <note>
     <para>
      On systems which differentiate between binary and text files 
      (i.e. Windows) the file must be opened with 'b' included in
      <function>fopen</function> mode parameter.
     </para>
    </note>
    <para>
     <informalexample>
      <programlisting role="php">
$filename = "c:\\files\\somepic.gif";
$fd = fopen ($filename, "rb");
$contents = fread ($fd, filesize ($filename));
fclose ($fd);
      </programlisting>
     </informalexample>
    </para>
    <simpara>
     See also <function>fwrite</function>, <function>fopen</function>,
     <function>fsockopen</function>, <function>popen</function>,
     <function>fgets</function>, <function>fgetss</function>,
     <function>fscanf</function>, <function>file</function>, and
     <function>fpassthru</function>.
    </simpara>
   </refsect1>
  </refentry>

  <refentry id="function.fscanf">
   <refnamediv>
    <refname>fscanf</refname>
    <refpurpose>Parses input from a file according to a format</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>mixed <function>fscanf</function></funcdef>
      <paramdef>int <parameter>handle</parameter></paramdef>
      <paramdef>string <parameter>format</parameter></paramdef>
      <paramdef>string 
       <parameter><optional>var1</optional></parameter>...
      </paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     The function <function>fscanf</function> is similar to
     <function>sscanf</function>, but it takes its input from a file
     associated with <parameter>handle</parameter> and interprets the
     input according to the specified
     <parameter>format</parameter>. If only two parameters were passed
     to this function, the values parsed will be returned as an array.
     Otherwise, if optional parameters are passed, the function will
     return the number of assigned values. The optional parameters
     must be passed by reference.
     <example>
      <title><function>fscanf</function> Example</title>
      <programlisting role="php">
$fp = fopen ("users.txt","r");
while ($userinfo = fscanf ($fp, "%s\t%s\t%s\n")) {
    list ($name, $profession, $countrycode) = $userinfo;
    //... do something with the values
}
fclose($fp);
      </programlisting>
     </example>
     <example>
      <title>users.txt</title>
      <programlisting>
javier  argonaut        pe
hiroshi sculptor        jp
robert  slacker us
luigi   florist it
      </programlisting>
     </example>
    </para>
    <para>
     See also <function>fread</function>, <function>fgets</function>,
     <function>fgetss</function>, <function>sscanf</function>,
     <function>printf</function>, and <function>sprintf</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.fseek">
   <refnamediv>
    <refname>fseek</refname>
    <refpurpose>Seeks on a file pointer</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>fseek</function></funcdef>
      <paramdef>int <parameter>fp</parameter></paramdef>
      <paramdef>int <parameter>offset</parameter></paramdef>
      <paramdef>int 
       <parameter><optional>whence</optional></parameter>
      </paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Sets the file position indicator for the file referenced by
     <parameter>fp</parameter>.The new position, measured in bytes
     from the beginning of the file, is obtained by adding
     <parameter>offset</parameter> to the position specified by
     <parameter>whence</parameter>, whose values are defined as
     follows:
     <simplelist>
      <member>SEEK_SET - Set position equal to
      <parameter>offset</parameter> bytes.</member> <member>SEEK_CUR -
      Set position to current location plus
      <parameter>offset</parameter>.</member> <member>SEEK_END - Set
      position to end-of-file plus
      <parameter>offset</parameter>.</member>
     </simplelist>
    </para>
    <para>If <parameter>whence is not specified, it is assumed to be
    SEEK_SET.</parameter>
    </para>
    <para>
     Upon success, returns 0; otherwise, returns -1. Note that seeking
     past EOF is not considered an error.
    </para>
    <para>
     May not be used on file pointers returned by
     <function>fopen</function> if they use the "http://" or "ftp://"
     formats.
    </para>
    <note>
     <para>
      The <parameter>whence</parameter> argument was added after PHP 4.0 RC1.
     </para>
    </note>
    <para>
     See also <function>ftell</function> and
     <function>rewind</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.fstat">
   <refnamediv>
    <refname>fstat</refname>
    <refpurpose>
     Gets information about a file using an open file pointer
    </refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>array <function>fstat</function></funcdef>
      <paramdef>int <parameter>fp</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Gathers the statistics of the file opened by the file
     pointer fp.  This function is similar to the
     <function>stat</function> function except that it operates
     on an open file pointer instead of a filename.
    </para>
    <para>
     Returns an array with the statistics of the file with the
     following elements:
     <orderedlist>
      <listitem><simpara>device</simpara></listitem>
      <listitem><simpara>inode</simpara></listitem>
      <listitem><simpara>number of links</simpara></listitem>
      <listitem><simpara>user id of owner</simpara></listitem>
      <listitem><simpara>group id owner</simpara></listitem>
      <listitem><simpara>device type if inode device *</simpara></listitem>
      <listitem><simpara>size in bytes</simpara></listitem>
      <listitem><simpara>time of last access</simpara></listitem>
      <listitem><simpara>time of last modification</simpara></listitem>
      <listitem><simpara>time of last change</simpara></listitem>
      <listitem><simpara>blocksize for filesystem I/O *</simpara></listitem>
      <listitem><simpara>number of blocks allocated</simpara></listitem>
     </orderedlist>
     * - only valid on systems supporting the st_blksize type--other
     systems (i.e. Windows) return -1</para>
    <para>
     The results of this function are cached. See
     <function>clearstatcache</function> for more details.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.ftell">
   <refnamediv>
    <refname>ftell</refname>
    <refpurpose>Tells file pointer read/write position</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>ftell</function></funcdef>
      <paramdef>int <parameter>fp</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Returns the position of the file pointer referenced by fp; i.e.,
     its offset into the file stream.
    </para>
    <para>
     If an error occurs, returns &false;.
    </para>
    <para>
     The file pointer must be valid, and must point to a file
     successfully opened by <function>fopen</function> or
     <function>popen</function>.
    </para>
    <para> 
     See also <function>fopen</function>, <function>popen</function>,
     <function>fseek</function> and <function>rewind</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.ftruncate">
   <refnamediv>
    <refname>ftruncate</refname>
    <refpurpose>
     Truncates a file to a given length.
    </refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>ftruncate</function></funcdef>
      <paramdef>int <parameter>fp</parameter></paramdef>
      <paramdef>int <parameter>size</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Takes the filepointer, fp, and truncates the file to length, size.
     This function returns &true; on success and &false; on failure.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.fwrite">
   <refnamediv>
    <refname>fwrite</refname>
    <refpurpose>Binary-safe file write</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>fwrite</function></funcdef>
      <paramdef>int <parameter>fp</parameter></paramdef>
      <paramdef>string <parameter>string</parameter></paramdef>
      <paramdef>int 
       <parameter>
        <optional>length</optional>
       </parameter>
      </paramdef>
     </funcprototype>
    </funcsynopsis>
    <simpara>
     <function>fwrite</function> writes the contents of
     <parameter>string</parameter> to the file stream pointed to by
     <parameter>fp</parameter>. If the <parameter>length</parameter>
     argument is given, writing will stop after
     <parameter>length</parameter> bytes have been written or the end
     of <parameter>string</parameter> is reached, whichever comes
     first.
    </simpara>
    <simpara>
     Note that if the <parameter>length</parameter> argument is given,
     then the <link
     linkend="ini.magic-quotes-runtime">magic_quotes_runtime</link>
     configuration option will be ignored and no slashes will be
     stripped from <parameter>string</parameter>.
    </simpara>
    <note>
     <para>
      On systems which differentiate between binary and text files 
      (i.e. Windows) the file must be opened with 'b' included in
      <function>fopen</function> mode parameter.
     </para>
    </note>
    <simpara>
     See also <function>fread</function>, <function>fopen</function>,
     <function>fsockopen</function>, <function>popen</function>, and
     <function>fputs</function>.
    </simpara>
   </refsect1>
  </refentry>

  <refentry id="function.set-file-buffer">
   <refnamediv>
    <refname>set_file_buffer</refname>
    <refpurpose>
     Sets file buffering on the given file pointer
    </refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>set_file_buffer</function></funcdef>
      <paramdef>int <parameter>fp</parameter></paramdef>
      <paramdef>int <parameter>buffer</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <simpara>
     Output using <function>fwrite</function> is normally buffered at
     8K.  This means that if there are two processess wanting to write
     to the same output stream (a file), each is paused after 8K of
     data to allow the other to write.  <function>set_file_buffer</function>
     sets the buffering for write operations on the given filepointer
     <parameter>fp</parameter> to <parameter>buffer</parameter> bytes.
     If <parameter>buffer</parameter> is 0 then write operations are
     unbuffered.  This ensures that all writes with
     <function>fwrite</function> are completed before other processes
     are allowed to write to that output stream.
    </simpara>
    <simpara>
     The function returns 0 on success, or EOF if the request cannot
     be honored.
    </simpara>
    <para>
     The following example demonstrates how to use
     <function>set_file_buffer</function> to create an unbuffered stream.
     <example>
      <title><function>set_file_buffer</function> example</title>
      <programlisting role="php">
$fp=fopen($file, "w");
if($fp){
  set_file_buffer($fp, 0);
  fputs($fp, $output);
  fclose($fp);
}
      </programlisting>
     </example>
    </para>

    <simpara>
     See also <function>fopen</function>, <function>fwrite</function>.
    </simpara>
   </refsect1>
  </refentry>

  <refentry id="function.is-dir">
   <refnamediv>
    <refname>is_dir</refname>
    <refpurpose>Tells whether the filename is a directory</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>is_dir</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Returns &true; if the filename exists and is a directory.
    </para>
    <para>
     The results of this function are cached. See
     <function>clearstatcache</function> for more details.
    </para>
    <simpara>
     This function will not work on <link
     linkend="features.remote-files">remote files</link>; the file to
     be examined must be accessible via the server's filesystem.
    </simpara>
    <para>
     See also <function>is_file</function> and
     <function>is_link</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.is-executable">
   <refnamediv>
    <refname>is_executable</refname>
    <refpurpose>Tells whether the filename is executable</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>is_executable</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Returns &true; if the filename exists and is executable.
    </para>
    <para>
     The results of this function are cached. See
     <function>clearstatcache</function> for more details.
    </para>
    <simpara>
     This function will not work on <link
     linkend="features.remote-files">remote files</link>; the file to
     be examined must be accessible via the server's filesystem.
    </simpara>
    <para>
     See also <function>is_file</function> and
     <function>is_link</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.is-file">
   <refnamediv>
    <refname>is_file</refname>
    <refpurpose>
     Tells whether the filename is a regular file
    </refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>is_file</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Returns &true; if the filename exists and is a regular file.
    </para>
    <para>
     The results of this function are cached. See
     <function>clearstatcache</function> for more details.
    </para>
    <para>
     See also <function>is_dir</function> and
     <function>is_link</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.is-link">
   <refnamediv>
    <refname>is_link</refname>
    <refpurpose>
     Tells whether the filename is a symbolic link
    </refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>is_link</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Returns &true; if the filename exists and is a symbolic link.
    </para>
    <para>
     The results of this function are cached. See
     <function>clearstatcache</function> for more details.
    </para>
    <para>
     See also <function>is_dir</function> and
     <function>is_file</function>.
    </para>
    <simpara>
     This function will not work on <link
     linkend="features.remote-files">remote files</link>; the file to
     be examined must be accessible via the server's filesystem.
    </simpara>
    <note>
     <simpara>
     This function does not work on Windows systems
     </simpara>
    </note>
   </refsect1>
  </refentry>

  <refentry id="function.is-readable">
   <refnamediv>
    <refname>is_readable</refname>
    <refpurpose>
     Tells whether the filename is readable
    </refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>is_readable</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Returns &true; if the filename exists and is readable.
    </para>
    <para>
     Keep in mind that PHP may be accessing the file as the user
     id that the web server runs as (often 'nobody'). Safe mode
     limitations are not taken into account.
    </para>
    <para>
     The results of this function are cached. See
     <function>clearstatcache</function> for more details.
    </para>
    <simpara>
     This function will not work on <link
     linkend="features.remote-files">remote files</link>; the file to
     be examined must be accessible via the server's filesystem.
    </simpara>
    <para>
     See also <function>is_writable</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.is-writable">
   <refnamediv>
    <refname>is_writable</refname>
    <refpurpose>Tells whether the filename is writable</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>is_writable</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Returns &true; if the filename exists and is writable.  The
     filename argument may be a directory name allowing you to check
     if a directory is writeable.
    </para>
    <para>
     Keep in mind that PHP may be accessing the file as the user id
     that the web server runs as (often 'nobody'). Safe mode
     limitations are not taken into account.
    </para>
    <para>
     The results of this function are cached. See
     <function>clearstatcache</function> for more details.
    </para>
    <simpara>
     This function will not work on <link
     linkend="features.remote-files">remote files</link>; the file to
     be examined must be accessible via the server's filesystem.
    </simpara>
    <para>
     See also <function>is_readable</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.is-writeable">
   <refnamediv>
    <refname>is_writeable</refname>
    <refpurpose>Tells whether the filename is writable</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>is_writeable</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     This is an alias for <function>is_writable</function>
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.is-uploaded-file">
   <refnamediv>
    <refname>is_uploaded_file</refname>
    <refpurpose>Tells whether the file was uploaded via HTTP POST.</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>is_uploaded_file</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>

    <para>
     This function is available only in versions of PHP 3 after PHP
     3.0.16, and in versions of PHP 4 after 4.0.2.
    </para>

    <para>
     Returns &true; if the file named by <varname>filename</varname> was
     uploaded via HTTP POST. This is useful to help ensure that a
     malicious user hasn't tried to trick the script into working on
     files upon which it should not be working--for instance,
     <filename>/etc/passwd</filename>.
    </para>

    <para>
     This sort of check is especially important if there is any chance
     that anything done with uploaded files could reveal their
     contents to the user, or even to other users on the same
     system.
    </para>

    <para>
     See also <function>move_uploaded_file</function>, and the section
     <link linkend="features.file-upload">Handling file uploads</link>
     for a simple usage example.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.link">
   <refnamediv>
    <refname>link</refname>
    <refpurpose>Create a hard link</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>link</function></funcdef>
      <paramdef>string <parameter>target</parameter></paramdef>
      <paramdef>string <parameter>link</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
    <function>link</function> creates a hard link.</para>
    <para>
     See also the <function>symlink</function> to create soft links,
     and <function>readlink</function> along with
     <function>linkinfo</function>.
    </para>
    <note>
     <simpara>
     This function does not work on Windows systems
     </simpara>
    </note>
   </refsect1>
  </refentry>

  <refentry id="function.linkinfo">
   <refnamediv>
    <refname>linkinfo</refname>
    <refpurpose>Gets information about a link</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>linkinfo</function></funcdef>
      <paramdef>string <parameter>path</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     <function>linkinfo</function> returns the st_dev field of the
     UNIX C stat structure returned by the lstat system call.  This
     function is used to verify if a link (pointed to by
     <parameter>path</parameter>) really exists (using the same method
     as the S_ISLNK macro defined in stat.h).  Returns 0 or &false; in
     case of error.
    </para>
    <para>
     See also <function>symlink</function>, <function>link</function>,
     and <function>readlink</function>.
    </para>
    <note>
     <simpara>
     This function does not work on Windows systems
     </simpara>
    </note>
   </refsect1>
  </refentry>

  <refentry id="function.mkdir">
   <refnamediv>
    <refname>mkdir</refname>
    <refpurpose>Makes directory</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>mkdir</function></funcdef>
      <paramdef>string <parameter>pathname</parameter></paramdef>
      <paramdef>int <parameter>mode</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Attempts to create the directory specified by pathname.
    </para>
    <para>
     Note that you probably want to specify the mode as an
     octal number, which means it should have a leading zero.
     The mode is also modified by the current umask, which you
     can change using <function>umask</function>.
     <informalexample>
      <programlisting role="php">
mkdir ("/path/to/my/dir", 0700);
      </programlisting>
     </informalexample>
    </para>
    <para>
     Returns &true; on success and &false; on failure.
    </para>
    <para>
     See also <function>rmdir</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.move-uploaded-file">
   <refnamediv>
    <refname>move_uploaded_file</refname>
    <refpurpose>Moves an uploaded file to a new location.</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>bool <function>move_uploaded_file</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
      <paramdef>string <parameter>destination</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>

    <para>
     This function is available only in versions of PHP 3 after PHP
     3.0.16, and in versions of PHP 4 after 4.0.2.
    </para>

    <para>
     This function checks to ensure that the file designated by
     <parameter>filename</parameter> is a valid upload file (meaning
     that it was uploaded via PHP's HTTP POST upload mechanism). If
     the file is valid, it will be moved to the filename given by
     <parameter>destination</parameter>.
    </para>

    <para>
     If <parameter>filename</parameter> is not a valid upload file,
     then no action will occur, and
     <function>move_uploaded_file</function> will return
     &false;. 
    </para>

    <para>
     If <parameter>filename</parameter> is a valid upload file, but
     cannot be moved for some reason, no action will occur, and
     <function>move_uploaded_file</function> will return
     &false;. Additionally, a warning will be issued.
    </para>

    <para>
     This sort of check is especially important if there is any chance
     that anything done with uploaded files could reveal their
     contents to the user, or even to other users on the same
     system.
    </para>

    &note.sm.uidcheck;

    <para>
     See also <function>is_uploaded_file</function>, and the section
     <link linkend="features.file-upload">Handling file uploads</link>
     for a simple usage example.
    </para>
   </refsect1>
  </refentry>


  <refentry id="function.pathinfo">
   <refnamediv>
    <refname>pathinfo</refname>
    <refpurpose>Returns information about a file path</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>array <function>pathinfo</function></funcdef>
      <paramdef>string <parameter>path</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     <function>pathinfo</function> returns an associative array
     containing information about <parameter>path</parameter>.  The
     following array elements are returned:
     <parameter>dirname</parameter>, <parameter>basename</parameter>
     and <parameter>extension</parameter>.
    </para>
    <para>
     <example>
      <title><function>pathinfo</function> Example</title>
      <programlisting role="php">
&lt;?php

$path_parts = pathinfo("/www/htdocs/index.html");

echo $path_parts["dirname"] . "\n";
echo $path_parts["basename"] . "\n";
echo $path_parts["extension"] . "\n";

?&gt;
      </programlisting>
     </example>
    </para>
    <para>
     Would produce:
     <informalexample>
      <programlisting>
/www/htdocs
index.html
html
      </programlisting>
     </informalexample>
    </para>
    <para>
     See also <function>dirname</function>,
     <function>basename</function> and <function>realpath</function>.
    </para>
   </refsect1>
  </refentry>


  <refentry id="function.pclose">
   <refnamediv>
    <refname>pclose</refname>
    <refpurpose>Closes process file pointer</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>pclose</function></funcdef>
      <paramdef>int <parameter>fp</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para> 
     Closes a file pointer to a pipe opened by
     <function>popen</function>.
    </para> 
    <para> 
     The file pointer must be valid, and must have been returned by a
     successful call to <function>popen</function>.
    </para> 
    <para>
     Returns the termination status of the process that was
     run.
    </para>
    <para>
     See also <function>popen</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.popen">
   <refnamediv>
    <refname>popen</refname>
    <refpurpose>Opens process file pointer</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>popen</function></funcdef>
      <paramdef>string <parameter>command</parameter></paramdef>
      <paramdef>string <parameter>mode</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para> 
     Opens a pipe to a process executed by forking the command given
     by command.
    </para>
    <para> 
     Returns a file pointer identical to that returned by
     <function>fopen</function>, except that it is unidirectional (may
     only be used for reading or writing) and must be closed with
     <function>pclose</function>. This pointer may be used with
     <function>fgets</function>, <function>fgetss</function>, and
     <function>fputs</function>.
    </para>
    <para>
     If an error occurs, returns &false;.
    </para>
    <para>
     <informalexample>
      <programlisting role="php">
$fp = popen ("/bin/ls", "r");
      </programlisting>
     </informalexample>
    </para>
    <para>
     See also <function>pclose</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.readfile">
   <refnamediv>
    <refname>readfile</refname>
    <refpurpose>Outputs a file</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>readfile</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
      <paramdef>int 
       <parameter>
        <optional>use_include_path</optional>
       </parameter>
      </paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Reads a file and writes it to standard output.
    </para>
    <para>
     Returns the number of bytes read from the file. If an error
     occurs, &false; is returned and unless the function was called as
     @readfile, an error message is printed.
    </para>
    <para>
     If <parameter>filename</parameter> begins with "http://"
     (not case sensitive), an HTTP 1.0 connection is opened to the
     specified server and the text of the response is written to
     standard output.
    </para>
    <para>
     Versions prior to PHP 4.0.5 do not handle HTTP redirects. Because
     of this, directories must include trailing slashes.
    </para>
    <para>
     If <parameter>filename</parameter> begins with "ftp://"
     (not case sensitive), an ftp connection to the specified server is
     opened and the requested file is written to standard output. If the server
     does not support passive mode ftp, this will fail.
    </para>
    <para>
     If <parameter>filename</parameter> begins with neither
     of these strings, the file will be opened from the filesystem and
     its contents written to standard output.
    </para>
    <para>
     You can use the optional second parameter and set it to "1", if
     you want to search for the file in the <link
     linkend="ini.include-path">include_path</link>, too.
    </para>
    <para>
     See also <function>fpassthru</function>,
     <function>file</function>, <function>fopen</function>,
     <function>include</function>, <function>require</function>, and
     <function>virtual</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.readlink">
   <refnamediv>
    <refname>readlink</refname>
    <refpurpose>Returns the target of a symbolic link</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>string <function>readlink</function></funcdef>
      <paramdef>string <parameter>path</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
    <function>readlink</function> does the same as the readlink C
    function and returns the contents of the symbolic link path or 0
    in case of error.
    </para>
    <para>
     See also <function>symlink</function>,
     <function>readlink</function> and
     <function>linkinfo</function>.
    </para>
    <note>
     <simpara>
     This function does not work on Windows systems
     </simpara>
    </note>
   </refsect1>
  </refentry>

  <refentry id="function.rename">
   <refnamediv>
    <refname>rename</refname>
    <refpurpose>Renames a file</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>rename</function></funcdef>
      <paramdef>string <parameter>oldname</parameter></paramdef>
      <paramdef>string <parameter>newname</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para> 
     Attempts to rename <parameter>oldname</parameter> to
     <parameter>newname</parameter>.
    </para> 
    <para> 
     Returns &true; on success and &false; on failure.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.rewind">
   <refnamediv>
    <refname>rewind</refname>
    <refpurpose>Rewind the position of a file pointer</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>rewind</function></funcdef>
      <paramdef>int <parameter>fp</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>    
     Sets the file position indicator for fp to the beginning of the
     file stream.</para> <para> If an error occurs, returns 0.</para>
     <para> The file pointer must be valid, and must point to a file
     successfully opened by <function>fopen</function>.
    </para>
    <para>
     See also <function>fseek</function> and
     <function>ftell</function>.
    </para>
   </refsect1>
  </refentry>


  <refentry id="function.rmdir">
   <refnamediv>
    <refname>rmdir</refname>
    <refpurpose>Removes directory</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>rmdir</function></funcdef>
      <paramdef>string <parameter>dirname</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para> 
     Attempts to remove the directory named by pathname. The directory
     must be empty, and the relevant permissions must permit.
     this.
    </para> 
    <para> 
     If an error occurs, returns 0.
    </para>
    <para>
     See also <function>mkdir</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.stat">
   <refnamediv>
    <refname>stat</refname>
    <refpurpose>Gives information about a file</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>array <function>stat</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Gathers the statistics of the file named by filename.
    </para>
    <para>
     Returns an array with the statistics of the file with the
     following elements:
     <orderedlist>
      <listitem><simpara>device</simpara></listitem>
      <listitem><simpara>inode</simpara></listitem>
      <listitem><simpara>inode protection mode</simpara></listitem>
      <listitem><simpara>number of links</simpara></listitem>
      <listitem><simpara>user id of owner</simpara></listitem>
      <listitem><simpara>group id owner</simpara></listitem>
      <listitem><simpara>device type if inode device *</simpara></listitem>
      <listitem><simpara>size in bytes</simpara></listitem>
      <listitem><simpara>time of last access</simpara></listitem>
      <listitem><simpara>time of last modification</simpara></listitem>
      <listitem><simpara>time of last change</simpara></listitem>
      <listitem><simpara>blocksize for filesystem I/O *</simpara></listitem>
      <listitem><simpara>number of blocks allocated</simpara></listitem>
     </orderedlist>
     * - only valid on systems supporting the st_blksize type--other
     systems (i.e. Windows) return -1.
    </para>
    <para>
     Returns &false; in case of error.
    </para>
    <para>
     <function>stat</function> doesn't handle URL as does <function>fopen</function>.
    </para>
    <para>
     The results of this function are cached. See
     <function>clearstatcache</function> for more details.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.lstat">
   <refnamediv>
    <refname>lstat</refname>
    <refpurpose>
     Gives information about a file or symbolic link
    </refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>array <function>lstat</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Gathers the statistics of the file or symbolic link named by
     filename.  This function is identical to the
     <function>stat</function> function except that if the
     <parameter>filename</parameter> parameter is a symbolic link, the
     status of the symbolic link is returned, not the status of the
     file pointed to by the symbolic link.
    </para>
    <para>
     Returns an array with the statistics of the file with the
     following elements:
     <orderedlist>
      <listitem><simpara>device</simpara></listitem>
      <listitem><simpara>inode</simpara></listitem>
      <listitem><simpara>inode protection mode</simpara></listitem>
      <listitem><simpara>number of links</simpara></listitem>
      <listitem><simpara>user id of owner</simpara></listitem>
      <listitem><simpara>group id owner</simpara></listitem>
      <listitem><simpara>device type if inode device *</simpara></listitem>
      <listitem><simpara>size in bytes</simpara></listitem>
      <listitem><simpara>time of last access</simpara></listitem>
      <listitem><simpara>time of last modification</simpara></listitem>
      <listitem><simpara>time of last change</simpara></listitem>
      <listitem><simpara>blocksize for filesystem I/O *</simpara></listitem>
      <listitem><simpara>number of blocks allocated</simpara></listitem>
     </orderedlist>
     * - only valid on systems supporting the st_blksize type--other
     systems (i.e. Windows) return -1</para>
    <para>
     The results of this function are cached. See
     <function>clearstatcache</function> for more details.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.realpath">
   <refnamediv>
    <refname>realpath</refname>
    <refpurpose>Returns canonicalized absolute pathname</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>string <function>realpath</function></funcdef>
      <paramdef>string <parameter>path</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     <function>realpath</function> expands all symbolic links and
     resolves references to '/./', '/../' and extra '/' characters in
     the input <parameter>path</parameter> and return the canonicalized
     absolute pathname.  The resulting path will have no symbolic link,
     '/./' or '/../' components.
    </para>
    <para>
     <example>
      <title><function>realpath</function> example</title>
      <programlisting role="php">
$real_path = realpath ("../../index.php");
      </programlisting>
     </example>
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.symlink">
   <refnamediv>
    <refname>symlink</refname>
    <refpurpose>Creates a symbolic link</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>symlink</function></funcdef>
      <paramdef>string <parameter>target</parameter></paramdef>
      <paramdef>string <parameter>link</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     <function>symlink</function> creates a symbolic link
     from the existing <parameter>target</parameter> with
     the specified name <parameter>link</parameter>.
    </para>
    <para>
     See also <function>link</function> to create hard links,
     and <function>readlink</function> along with
     <function>linkinfo</function>.
    </para>
    <note>
     <simpara>
      This function does not work on Windows systems.
     </simpara>
    </note>
   </refsect1>
  </refentry>

  <refentry id="function.tempnam">
   <refnamediv>
    <refname>tempnam</refname>
    <refpurpose>Creates unique file name</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>string <function>tempnam</function></funcdef>
      <paramdef>string <parameter>dir</parameter></paramdef>
      <paramdef>string <parameter>prefix</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Creates a unique temporary filename in the specified directory.
     If the directory does not exist, <function>tempnam</function> may
     generate a filename in the system's temporary directory.
    </para>
    <para>
     Prior to PHP 4.0.6, the behaviour of the
     <function>tempnam</function> function was system dependent. On
     Windows the TMP environment variable will override the
     <parameter>dir</parameter> parameter, on Linux the TMPDIR
     environment variable has precedence, while SVR4 will always use
     your <parameter>dir</parameter> parameter if the directory it
     points to exists. Consult your system documentation on the
     tempnam(3) function if in doubt.
    </para>
    <para>
     Returns the new temporary filename, or the &null; string on
     failure.
     <example>
      <title><function>tempnam</function> example</title>
      <programlisting role="php">
$tmpfname = tempnam ("/tmp", "FOO");
      </programlisting>
     </example>
    </para>
    <note>
     <simpara>
      This function's behavior changed in 4.0.3. The temporary file is also
      created to avoid a race condition where the file might appear in the
      filesystem between the time the string was generated and before the
      the script gets around to creating the file. 
     </simpara>
    </note>
    <para>
     See also <function>tmpfile</function>.
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.tmpfile">
   <refnamediv>
    <refname>tmpfile</refname>
    <refpurpose>Creates a temporary file</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>tmpfile</function></funcdef>
      <void/>
     </funcprototype>
    </funcsynopsis>
    <para>
     Creates a temporary file with an unique name in write mode,
     returning a file handle similar to the one returned by
     <function>fopen</function>.
     The file is automatically removed when closed (using
     <function>fclose</function>), or when the script ends.
    </para>
    <para>
     For details, consult your system documentation on the
     <literal>tmpfile(3)</literal> function, as well as the
     <filename>stdio.h</filename> header file.
    </para>
    <para>
     See also <function>tempnam</function>.
    </para>
   </refsect1>
  </refentry>


  <refentry id="function.touch">
   <refnamediv>
    <refname>touch</refname>
    <refpurpose>Sets modification time of file</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>touch</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
      <paramdef>int 
        <parameter>
         <optional>time</optional>
        </parameter>
      </paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Attempts to set the modification time of the file named by
     filename to the value given by time. If the option time is not
     given, uses the present time.
    </para>
    <para>
     If the file does not exist, it is created.
    </para>
    <para>
     Returns &true; on success and &false; otherwise.
     <example>
      <title><function>touch</function> example</title>
      <programlisting role="php">
if (touch ($FileName)) {
    print "$FileName modification time has been 
           changed to todays date and time";
} else {
    print "Sorry Could Not change modification time of $FileName";
}
      </programlisting>
     </example>
    </para>
   </refsect1>
  </refentry>

  <refentry id="function.umask">
   <refnamediv>
    <refname>umask</refname>
    <refpurpose>Changes the current umask</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>umask</function></funcdef>
      <paramdef>int <parameter>mask</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     <function>umask</function> sets PHP's umask to mask &amp; 0777 and
     returns the old umask. When PHP is being used as a server module,
     the umask is restored when each request is finished.
    </para>
    <para>
     <function>umask</function> without arguments simply returns the
     current umask.
    </para>
    <note>
     <simpara>
      This function may not work on Windows systems.
     </simpara>
    </note>
   </refsect1>
  </refentry>

  <refentry id="function.unlink">
   <refnamediv>
    <refname>unlink</refname>
    <refpurpose>Deletes a file</refpurpose>
   </refnamediv>
   <refsect1>
    <title>Description</title>
    <funcsynopsis>
     <funcprototype>
      <funcdef>int <function>unlink</function></funcdef>
      <paramdef>string <parameter>filename</parameter></paramdef>
     </funcprototype>
    </funcsynopsis>
    <para>
     Deletes <parameter>filename</parameter>.  Similar to the Unix C
     unlink() function.
    </para>
    <para>
     Returns 0 or &false; on an error.
    </para>
    <para>
     See also <function>rmdir</function> for removing directories.
    </para>
    <note>
     <simpara>
      This function may not work on Windows systems.
     </simpara>
    </note>
   </refsect1>
  </refentry>

 </reference>

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