<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>
</funcprototype>
</funcsynopsis>
<para>
Given a string containing a path to a file, this function will
return the base name of the file.
</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"
</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_writeable</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...<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.fclose">
<refnamediv>
<refname>fclose</refname>
<refpurpose>Closes an open file pointer</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcprototype>
<funcdef>int <function>fclose</function></funcdef>
<paramdef>int <parameter>fp</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<para>
The file pointed to by fp 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.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 "<p> $num fields in line $row: <br>";
$row++;
for ($c=0; $c<$num; $c++) {
print $data[$c] . "<br>";
}
}
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">
<?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 "<b>Line $line_num:</b> " . htmlspecialchars ($line) . "<br>\n";
}
// get a web page into a string
$fcontents = join ('', file ('http://www.php.net'));
?>
</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>
<function>file_exists</function> will not work on remote files;
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 appliation 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>
</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 filesystem, a file is considered
changed, when it's Inode data is changed, that is, when
the permissions, the owner, the group or other metadata
from the Inode is written to. See also
<function>filemtime</function> (this is what you want to use
when you want to create "Last Modified" footers on web pages) and
<function>fileatime</function>.
</para>
<para>Note: In some Unix texts the ctime of a file is being
referred to as the creation time of the file. This is wrong.
There is no creation time for Unix files in most Unix
filesystems.
</para>
</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>
</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>
<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>
<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>
<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>
<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>
</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>
</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 and a file pointer is returned to the beginning
of the text of the response. A 'Host:' header is sent with the
request in order to handle name-based virtual hosts.
</simpara>
<simpara>
Does not handle HTTP redirects, so you must include trailing
slashes on directories.
</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 and 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>
The <parameter>mode</parameter> may contain the letter
'b'. This is useful only on systems which differentiate between
binary and text files (i.e., it's useless on Unix). If not
needed, this will be ignored.
</para>
<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>
<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>
<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>
<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>
<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>
<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>
<para>
See also <function>is_writeable</function>.
</para>
</refsect1>
</refentry>
<refentry id="function.is-writeable">
<refnamediv>
<refname>is_writeable</refname>
<refpurpose>Tells whether the filename is writeable</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcprototype>
<funcdef>bool <function>is_writeable</function></funcdef>
<paramdef>string <parameter>filename</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<para>
Returns true if the filename exists and is writeable. 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>
<para>
See also <function>is_readable</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.
<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
<literal>false</literal>.
</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
<literal>false</literal>. 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>
<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.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>
Does not handle HTTP redirects, so you must include trailing
slashes on directories.
</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>
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>
The behaviour of the <function>tempnam</function> function is
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">
$tmpfname = tempnam ("/tmp", "FOO");
</programlisting>
</example>
</para>
<para>
See also <function>tmpfile</function>.
</para>
</refsect1>
</refentry>
<refentry id="function.tmpfile">
<refnamediv>
<refname>tmpfile</refname>
<refpurpose>Creates a temporary file</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcprototype>
<funcdef>int <function>tmpfile</function></funcdef>
<paramdef>void</paramdef>
</funcprototype>
</funcsynopsis>
<para>
Creates a temporary file with an unique name in write mode,
returning a file handle similar to the one returned by
<function>fopen</function>.
The file is automatically removed when closed (using
<function>fclose</function>), or when the script ends.
</para>
<para>
For details, consult your system documentation on the
<literal>tmpfile(3)</literal> function, as well as the
<filename>stdio.h</filename> header file.
</para>
<para>
See also <function>tempnam</function>.
</para>
</refsect1>
</refentry>
<refentry id="function.touch">
<refnamediv>
<refname>touch</refname>
<refpurpose>Sets modification time of file</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcprototype>
<funcdef>int <function>touch</function></funcdef>
<paramdef>string <parameter>filename</parameter></paramdef>
<paramdef>int
<parameter>
<optional>time</optional>
</parameter>
</paramdef>
</funcprototype>
</funcsynopsis>
<para>
Attempts to set the modification time of the file named by
filename to the value given by time. If the option time is not
given, uses the present time.
</para>
<para>
If the file does not exist, it is created.
</para>
<para>
Returns true on success and false otherwise.
<example>
<title><function>Touch</function> example</title>
<programlisting role="php">
if (touch ($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 & 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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