©
Dokumen ini menggunakan Manual laman web PHP Cina Lepaskan
(PHP 5, PHP 7)
file_put_contents — 将一个字符串写入文件
$filename
, mixed $data
[, int $flags
= 0
[, resource $context
]] )和依次调用 fopen() , fwrite() 以及 fclose() 功能一样。
If filename
does not exist, the file is created.
Otherwise, the existing file is overwritten, unless the
FILE_APPEND
flag is set.
filename
要被写入数据的文件名。
data
要写入的数据。类型可以是 string , array 或者是 stream 资源(如上面所说的那样)。
如果 data
指定为 stream 资源,这里 stream
中所保存的缓存数据将被写入到指定文件中,这种用法就相似于使用
stream_copy_to_stream() 函数。
参数 data
可以是数组(但不能为多维数组),这就相当于
file_put_contents($filename, join('', $array))。
flags
flags
的值可以是
以下 flag 使用 OR (|) 运算符进行的组合。
Flag | 描述 |
---|---|
FILE_USE_INCLUDE_PATH |
在 include 目录里搜索 filename 。
更多信息可参见 include_path。
|
FILE_APPEND |
如果文件 filename 已经存在,追加数据而不是覆盖。
|
LOCK_EX | 在写入时获得一个独占锁。 |
context
一个 context 资源。
该函数将返回写入到文件内数据的字节数,失败时返回 FALSE
此函数可能返回布尔值
FALSE
,但也可能返回等同于 FALSE
的非布尔值。请阅读 布尔类型章节以获取更多信息。应使用
===
运算符来测试此函数的返回值。
Example #1 Simple usage example
<?php
$file = 'people.txt' ;
// Open the file to get existing content
$current = file_get_contents ( $file );
// Append a new person to the file
$current .= "John Smith\n" ;
// Write the contents back to the file
file_put_contents ( $file , $current );
?>
Example #2 Using flags
<?php
$file = 'people.txt' ;
// The new person to add to the file
$person = "John Smith\n" ;
// Write the contents to the file,
// using the FILE_APPEND flag to append the content to the end of the file
// and the LOCK_EX flag to prevent anyone else writing to the file at the same time
file_put_contents ( $file , $person , FILE_APPEND | LOCK_EX );
?>
版本 | 说明 |
---|---|
5.0.0 | Added context support |
5.1.0 |
添加了对 LOCK_EX 的支持和 data
参数处理 stream 资源的功能。
|
Note: 此函数可安全用于二进制对象。
如已启用fopen 包装器,在此函数中, URL 可作为文件名。关于如何指定文件名详见 fopen() 。各种 wapper 的不同功能请参见 支持的协议和封装协议,注意其用法及其可提供的预定义变量。
[#1] Nadeem [2014-11-28 10:01:42]
Log custom or error messages to a file.
<?php
class Logger{
protected $file;
protected $content;
protected $writeFlag;
protected $endRow;
public function __construct($file,$endRow="\n",$writeFlag=FILE_APPEND) {
$this->file=$file;
$this->writeFlag=$writeFlag;
$this->endRow=$endRow;
}
public function AddRow($content="",$newLines=1){
for ($m=0;$m<$newLines;$m++)
{
$newRow .= $this->endRow;
}
$this->content .= $content . $newRow;
}
public function Commit(){
return file_put_contents($this->file,$this->content,$this->writeFlag);
}
public function LogError($error,$newLines=1)
{
if ($error!=""){
$this->AddRow($error,$newLines);
echo $error;
}
}
}
$logFileDirectoryAndName="/yourDirectory/yourFileName.xxx";
$logger = new Logger($logFileDirectoryAndName);
$logger->AddRow("Your Log Message");
#log a system error and echo a message
$logger->LogError(mysql_error($conn));
$logger->Commit();
?>
[#2] gurjindersingh at SPAM dot hotmail dot com [2014-10-18 18:03:10]
File put contents fails if you try to put a file in a directory that doesn't exist. This function creates the directory.
i have updated code of "TrentTompkins at gmail dot com". thanks
<?php
function file_force_contents($filename, $data, $flags = 0){
if(!is_dir(dirname($filename)))
mkdir(dirname($filename).'/', 0777, TRUE);
return file_put_contents($filename, $data,$flags);
}
// usage
file_force_contents('test1.txt','test1 content'); // test1.txt created
file_force_contents('test2/test2.txt','test2 content');
// test2/test2.txt created "test2" folder.
file_force_contents('~/test3/test3.txt','test3 content');
// /path/to/user/directory/test3/test3.txt created "test3" folder in user directory (check on linux "ll ~/ | grep test3").
?>
[#3] klunker dot roox at gmail dot com [2014-10-17 10:47:47]
if path to the file not exist function file_put_contents can't create it. This simple function make it on UNIX-based and Windows servers.
<?php
function file_put_contents_force(){
$args = func_get_args();
$path = str_replace(array('/','\\'), DIRECTORY_SEPARATOR, $args[0]);
$parts = explode(DIRECTORY_SEPARATOR, $path);
array_pop($parts);
$directory = '';
foreach($parts as $part):
$check_path = $directory.$part;
if( is_dir($check_path.DIRECTORY_SEPARATOR) === FALSE) {
mkdir($check_path, 0755);
}
$directory = $check_path.DIRECTORY_SEPARATOR;
endforeach;
call_user_func_array('file_put_contents',$args);
}
?>
[#4] chris at ocportal dot com [2013-07-28 11:13:11]
It's important to understand that LOCK_EX will not prevent reading the file unless you also explicitly acquire a read lock (shared locked) with the PHP 'flock' function.
i.e. in concurrent scenarios file_get_contents may return empty if you don't wrap it like this:
<?php
$myfile=fopen('test.txt','rt');
flock($myfile,LOCK_SH);
$read=file_get_contents('test.txt');
fclose($myfile);
?>
If you have code that does a file_get_contents on a file, changes the string, then re-saves using file_put_contents, you better be sure to do this correctly or your file will randomly wipe itself out.
[#5] michel kollenhoven [2013-07-19 09:35:00]
re: moura dot kadu at gmail dot com
why not ? file_put_contents('ftp://user:pass@server/path/to/file',$data);
[#6] vahkos at mail dot ru [2012-01-22 20:06:53]
file_put_contents does not issue an error message if file name is incorrect(for example has improper symbols on the end of it /n,/t)
that is why use trim() for file name.
$name=trim($name);
file_put_contents($name,$content);
[#7] caiofior at gmail dot com [2011-10-27 01:56:43]
I had some troubles using file_put_contents with an absolute but no canonicalized path (eg. w:/htdocs/pri/../test/log.txt): on windows environment php was unable to create the file also using the realpath function .
I had to use fopen and frwite functions to write the data.
[#8] moura dot kadu at gmail dot com [2011-09-23 12:18:04]
I made ??a ftp_put_contents function.
hope you enjoy.
<?php
function ftp_put_contents($fpc_path_and_name, $fpc_content) {
//Temporary folder in the server
$cfg_temp_folder = str_replace("//", "/", $_SERVER['DOCUMENT_ROOT']."/_temp/");
//Link to FTP
$cfg_ftp_server = "ftp://ftp.com";
//FTP username
$cfg_user = "user";
//FTP password
$cfg_pass = "password";
//Document Root of FTP
$cfg_document_root = "DOCUMENT ROOT OF FTP";
//Link to the website
$cfg_site_link = "Link to the website";
//Check if conteins slash on the path of the file
$cotains_slash = strstr($fpc_path_and_name, "/");
//Get filename and paths
if ($cotains_slash) {
$fpc_path_and_name_array = explode("/", $fpc_path_and_name);
$fpc_file_name = end($fpc_path_and_name_array);
}
else {
$fpc_file_name = $fpc_path_and_name;
}
//Create local temp dir
if (!file_exists($cfg_temp_folder)) {
if (!mkdir($cfg_temp_folder, 0777)) {
echo "Unable to generate a temporary folder on the local server - $cfg_temp_folder.<br />";
die();
}
}
//Create local file in temp dir
if (!file_put_contents(str_replace("//", "/", $cfg_temp_folder.$fpc_file_name), $fpc_content)) {
echo "Unable to generate the file in the temporary location - ".str_replace("//", "/", $cfg_temp_folder.$fpc_file_name).".<br />";
die();
}
//Connection to the FTP Server
$fpc_ftp_conn = ftp_connect("$cfg_ftp_server");
//Check connection
if (!$fpc_ftp_conn) {
echo "Could not connect to server <b>$cfg_ftp_server</b>.<br />";
die();
}
else {
// login
// check username and password
if (!ftp_login($fpc_ftp_conn, "$cfg_user", "$cfg_pass")) {
echo "User or password.<br />";
die();
}
else {
//Document Root
if (!ftp_chdir($fpc_ftp_conn, $cfg_document_root)) {
echo "Error to set Document Root.<br />";
die();
}
//Check if there are folders to create
if ($cotains_slash) {
//Check if have folders and is not just the file name
if (count($fpc_path_and_name_array) > 1) {
//Remove last array
$fpc_remove_last_array = array_pop($fpc_path_and_name_array);
//Checks if there slashs on the path
if (substr($fpc_path_and_name,0,1) == "/") {
$fpc_remove_first_array = array_shift($fpc_path_and_name_array);
}
//Create each folder on ftp
foreach ($fpc_path_and_name_array as $fpc_ftp_path) {
if (!@ftp_chdir($fpc_ftp_conn, $fpc_ftp_path)) {
if (!ftp_mkdir($fpc_ftp_conn, $fpc_ftp_path)) {
echo "Error creating directory $fpc_ftp_path.<br />";
}
else {
if (!ftp_chdir($fpc_ftp_conn, $fpc_ftp_path)) {
echo "Error go to the directory $fpc_ftp_path.<br />";
}
}
}
}
}
else {
}
}
//Check upload file
if (!ftp_put($fpc_ftp_conn, $fpc_file_name, str_replace("//", "/", $cfg_temp_folder.$fpc_file_name), FTP_ASCII)) {
echo "File upload <b>$fpc_path_and_name</b> failed!<br />";
die();
}
else {
if (!unlink(str_replace("//", "/", $cfg_temp_folder.$fpc_file_name))) {
echo "Error deleting temporary file.<br />";
die();
}
else {
echo "File upload <a href='$cfg_site_link".str_replace("//", "/", "/$fpc_path_and_name")."'><b>$cfg_site_link".str_replace("//", "/", "/$fpc_path_and_name")."</a></b> successfully performed.<br />";
}
}
//Close connection to FTP server
ftp_close($fpc_ftp_conn);
}
}
}
#Sample
$content_file = "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Transitional//EN\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd\">
<html xmlns=\"http://www.w3.org/1999/xhtml\">
<head>
<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\" />
<title>Title</title>
</head>
<body>
<p>Test</p>
</body>
</html>";
ftp_put_contents("test.php", $content_file);
?>
[#9] justin dot carlson at gmail dot com [2011-08-16 08:28:26]
It should be obvious that this should only be used if you're making one write, if you are writing multiple times to the same file you should handle it yourself with fopen and fwrite, the fclose when you are done writing.
Benchmark below:
file_put_contents() for 1,000,000 writes - average of 3 benchmarks:
real 0m3.932s
user 0m2.487s
sys 0m1.437s
fopen() fwrite() for 1,000,000 writes, fclose() - average of 3 benchmarks:
real 0m2.265s
user 0m1.819s
sys 0m0.445s
[#10] Brandon Lockaby [2011-07-08 10:56:09]
Calling file_put_contents within a destructor will cause the file to be written in SERVER_ROOT...
[#11] ravianshmsr08 at gmail dot com [2010-12-15 01:39:47]
To upload file from your localhost to any FTP server.
pease note 'ftp_chdir' has been used instead of putting direct remote file path....in ftp_put ...remoth file should be only file name
<?php
$host = '*****';
$usr = '*****';
$pwd = '**********';
$local_file = './orderXML/order200.xml';
$ftp_path = 'order200.xml';
$conn_id = ftp_connect($host, 21) or die ("Cannot connect to host");
ftp_pasv($resource, true);
ftp_login($conn_id, $usr, $pwd) or die("Cannot login");
// perform file upload
ftp_chdir($conn_id, '/public_html/abc/');
$upload = ftp_put($conn_id, $ftp_path, $local_file, FTP_ASCII);
if($upload) { $ftpsucc=1; } else { $ftpsucc=0; }
// check upload status:
print (!$upload) ? 'Cannot upload' : 'Upload complete';
print "\n";
// close the FTP stream
ftp_close($conn_id);
?>
[#12] error at example dot com [2010-12-11 12:47:20]
It's worth noting that you must make sure to use the correct path when working with this function. I was using it to help with logging in an error handler and sometimes it would work - while other times it wouldn't. In the end it was because sometimes it was called from different paths resulting in a failure to write to the log file.
__DIR__ is your friend.
[#13] hilton at allcor dot com dot br [2010-11-04 04:20:50]
NOTE : file_put_contents create files UTF-8
<?php
$myFile = 'test.txt';
$myContent = 'I love PHP';
file_put_contents($myFile, utf8_encode($myContent));
?>
[#14] clement dot delmas at gmail dot com [2010-09-17 06:22:36]
NOTE : file_put_contents doesn't add a valid BOM while creating the file
<?php
$myFile = 'test.txt';
$myContent = 'I love PHP';
file_put_contents($myFile, "\xEF\xBB\xBF".$myContent);
?>
[#15] deqode at felosity dot nl [2010-02-15 12:14:42]
Please note that when saving using an FTP host, an additional stream context must be passed through telling PHP to overwrite the file.
<?php
$user = "test";
$pass = "myFTP";
$host = "example.com";
$file = "test.txt";
$hostname = $user . ":" . $pass . "@" . $host . "/" . $file;
$content = "this is just a test.";
$options = array('ftp' => array('overwrite' => true));
$stream = stream_context_create($options);
file_put_contents($hostname, $content, 0, $stream);
?>
[#16] John Galt [2009-07-29 12:14:08]
I use file_put_contents() as a method of very simple hit counters. These are two different examples of extremely simple hit counters, put on one line of code, each.
Keep in mind that they're not all that efficient. You must have a file called counter.txt with the initial value of 0.
For a text hit counter:
<?php
$counter = file_get_contents("counter.txt"); $counter++; file_put_contents("counter.txt", $counter); echo $counter;
?>
Or a graphic hit counter:
<?php
$counter = file_get_contents("counter.txt"); $counter++; file_put_contents("counter.txt", $counter); for($i = 0; $i < strlen($counter); $i++) echo "<img src=\"counter/".substr($counter, $i, 1).".gif\" alt=\"".substr($counter, $i, 1)."\" />";
?>
[#17] wjsams at gmail dot com [2009-06-25 08:57:58]
file_put_contents() strips the last line ending
If you really want an extra line ending at the end of a file when writing with file_put_contents(), you must append an extra PHP_EOL to the end of the line as follows.
<?php
$a_str = array("these","are","new","lines");
$contents = implode(PHP_EOL, $a_str);
$contents .= PHP_EOL . PHP_EOL;
file_put_contents("newfile.txt", $contents);
print("|$contents|");
?>
You can see that when you print $contents you get two extra line endings, but if you view the file newfile.txt, you only get one.
[#18] kola_lola at hotmail dot com [2008-11-06 15:31:46]
I wrote this script implementing the file_put_contents() and file_get_contents() functions to be compatible with both php4.* and php 5.*. It is a PHP Command line interface script which searches and replaces a specific word recursively through all files in the supplied directory hierarchy.
Usage from a Linux command line: ./scriptname specifieddirectory searchString replaceString
#!/usr/bin/php
<?php
$argc = $_SERVER['argc'];
$argv = $_SERVER['argv'];
if($argc != 4)
{
echo "This command replaces a search string with a replacement string\n for the contents of all files in a directory hierachy\n";
echo "command usage: $argv[0] directory searchString replaceString\n";
echo "\n";
exit;
}
?>
<?php
if (!function_exists('file_put_contents')) {
function file_put_contents($filename, $data) {
$f = @fopen($filename, 'w');
if (!$f) {
return false;
} else {
$bytes = fwrite($f, $data);
fclose($f);
return $bytes;
}
}
}
function get_file_contents($filename)
{
if (!function_exists('file_get_contents'))
{
$fhandle = fopen($filename, "r");
$fcontents = fread($fhandle, filesize($filename));
fclose($fhandle);
}
else
{
$fcontents = file_get_contents($filename);
}
return $fcontents;
}
?>
<?php
function openFileSearchAndReplace($parentDirectory, $searchFor, $replaceWith)
{
//echo "debug here- line 1a\n";
//echo "$parentDirectory\n";
//echo "$searchFor\n";
//echo "$replaceWith\n";
if ($handle = opendir("$parentDirectory")) {
while (false !== ($file = readdir($handle))) {
if (($file != "." && $file != "..") && !is_dir($file)) {
chdir("$parentDirectory"); //to make sure you are always in right directory
// echo "$file\n";
$holdcontents = file_get_contents($file);
$holdcontents2 = str_replace($searchFor, $replaceWith, $holdcontents);
file_put_contents($file, $holdcontents2);
// echo "debug here- line 1\n";
// echo "$file\n";
}
if(is_dir($file) && ($file != "." && $file != ".."))
{
$holdpwd = getcwd();
//echo "holdpwd = $holdpwd \n";
$newdir = "$holdpwd"."/$file";
//echo "newdir = $newdir \n"; //for recursive call
openFileSearchAndReplace($newdir, $searchFor, $replaceWith);
//echo "debug here- line 2\n";
//echo "$file\n";
}
}
closedir($handle);
}
}
$parentDirectory2 = $argv[1];
$searchFor2 = $argv[2];
$replaceWith2 = $argv[3];
//Please do not edit below to keep the rights to this script
//Free license, if contents below this line is not edited
echo "REPLACED\n'$searchFor2' with '$replaceWith2' recursively through directory listed below\nFor all files that current user has write permissions for\nDIRECTORY: '$parentDirectory2'\n";
echo "command written by Kolapo Akande :) all rights reserved :)\n";
$holdpwd = getcwd();
//echo "$holdpwd\n";
chdir($parentDirectory2);
openFileSearchAndReplace($parentDirectory2, $searchFor2, $replaceWith2);
exit;
?>
[#19] admin at nabito dot net [2008-08-04 01:11:21]
This is example, how to save Error Array into simple log file
<?php
$error[] = 'some error';
$error[] = 'some error 2';
@file_put_contents('log.txt',date('c')."\n".implode("\n", $error),FILE_APPEND);
?>
[#20] TrentTompkins at gmail dot com [2008-07-02 05:25:25]
File put contents fails if you try to put a file in a directory that doesn't exist. This creates the directory.
<?php
function file_force_contents($dir, $contents){
$parts = explode('/', $dir);
$file = array_pop($parts);
$dir = '';
foreach($parts as $part)
if(!is_dir($dir .= "/$part")) mkdir($dir);
file_put_contents("$dir/$file", $contents);
}
?>
[#21] Anonymous [2008-05-02 11:06:15]
file_put_contents() will cause concurrency problems - that is, it doesn't write files atomically (in a single operation), which sometimes means that one php script will be able to, for example, read a file before another script is done writing that file completely.
The following function was derived from a function in Smarty (http://smarty.php.net) which uses rename() to replace the file - rename() is atomic on Linux.
On Windows, rename() is not currently atomic, but should be in the next release. Until then, this function, if used on Windows, will fall back on unlink() and rename(), which is still not atomic...
<?php
define("FILE_PUT_CONTENTS_ATOMIC_TEMP", dirname(__FILE__)."/cache");
define("FILE_PUT_CONTENTS_ATOMIC_MODE", 0777);
function file_put_contents_atomic($filename, $content) {
$temp = tempnam(FILE_PUT_CONTENTS_ATOMIC_TEMP, 'temp');
if (!($f = @fopen($temp, 'wb'))) {
$temp = FILE_PUT_CONTENTS_ATOMIC_TEMP . DIRECTORY_SEPARATOR . uniqid('temp');
if (!($f = @fopen($temp, 'wb'))) {
trigger_error("file_put_contents_atomic() : error writing temporary file '$temp'", E_USER_WARNING);
return false;
}
}
fwrite($f, $content);
fclose($f);
if (!@rename($temp, $filename)) {
@unlink($filename);
@rename($temp, $filename);
}
@chmod($filename, FILE_PUT_CONTENTS_ATOMIC_MODE);
return true;
}
?>
[#22] the geek man at hot mail point com [2008-01-03 03:23:00]
I use the following code to create a rudimentary text editor. It's not fancy, but then it doesn't have to be. You could easily add a parameter to specify a file to edit; I have not done so to avoid the potential security headaches.
There are still obvious security holes here, but for most applications it should be reasonably safe if implemented for brief periods in a counterintuitive spot. (Nobody says you have to make a PHP file for that purpose; you can tack it on anywhere, so long as it is at the beginning of a file.)
<?php
$random1 = 'randomly_generated_string';
$random2 = 'another_randomly_generated_string';
$target_file = 'file_to_edit.php';
$this_file = 'the_current_file.php';
if ($_REQUEST[$random1] === $random2) {
if (isset($_POST['content']))
file_put_contents($target_file, get_magic_quotes_qpc() ? stripslashes($_POST['content']) : $_POST['content']);
die('<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<title>Editing...</title>
</head>
<body>
<form method="post" action="' . $this_file . '" />
<input type="hidden" name="' . $random1 . '" value="' . $random2 . '" />
<textarea name="content" rows="50" cols="100">' . file_get_contents($target_file) . '</textarea><br />
<input type="submit" value="Save Changes" />
</form>
</body>
</html>');
}
?>
Then simply browse to hxxp://www.example.com/{$this_file}?{$random1}={$random2}, with the appropriate values substituted for each bracketed variable. Please note that this code assumes the target file to be world writable (-rw-rw-rw- or 666) and will fail to save properly without error if it is not.
Once again, this is by no means secure or permanent, but as a quick fix for brief edits to noncritical files it should be sufficient, and its small size is a definite bonus.
[#23] egingell at sisna dot com [2007-12-20 19:15:30]
There is a better way. www.php.net/touch
Since you're not adding anything to the file,
<?php
function updateFile($filename) {
if (!file_exists($filename)) return;
touch($filename);
}
?>
[#24] Curtis [2006-12-21 03:20:32]
As to the previous user note, it would be wise to include that code within a conditional statement, as to prevent re-defining file_put_contents and the FILE_APPEND constant in PHP 5:
<?php
if ( !function_exists('file_put_contents') && !defined('FILE_APPEND') ) {
...
}
?>
Also, if the file could not be accessed for writing, the function should return boolean false, not 0. An error is different from 0 bytes written, in this case.
[#25] egingell at sisna dot com [2006-07-23 04:11:30]
In reply to the previous note:
If you want to emulate this function in PHP4, you need to return the bytes written as well as support for arrays, flags.
I can only figure out the FILE_APPEND flag and array support. If I could figure out "resource context" and the other flags, I would include those too.
<?php
define('FILE_APPEND', 1);
function file_put_contents($n, $d, $flag = false) {
$mode = ($flag == FILE_APPEND || strtoupper($flag) == 'FILE_APPEND') ? 'a' : 'w';
$f = @fopen($n, $mode);
if ($f === false) {
return 0;
} else {
if (is_array($d)) $d = implode($d);
$bytes_written = fwrite($f, $d);
fclose($f);
return $bytes_written;
}
}
?>
[#26] sendoshin at awswan dot com [2006-03-05 23:01:04]
To clear up what was said by pvenegas+php at gmail dot com on 11-Oct-2005 08:13, file_put_contents() will replace the file by default. Here's the complete set of rules this function follows when accessing a file:
1. Was FILE_USE_INCUDE_PATH passed in the call? If so, check the include path for an existing copy of *filename*.
2. Does the file already exist? If not, first create it in the current working directory. Either way, open the file.
3. Was LOCK_EX passed in the call? If so, lock the file.
4. Was the function called with FILE_APPEND? If not, clear the file's contents. Otherwise, move to the end of the file.
5. Write *data* into the file.
6. Close the file and release any locks.
If you don't want to completely replace the contents of the file you're writing to, be sure to use FILE_APPEND (same as fopen() with 'a') in the *flags*. If you don't, whatever used to be there will be gone (fopen() with 'w').
Hope that helps someone (and that it makes sense ^^)!
- Sendoshin
[#27] aidan at php dot net [2004-05-20 19:11:29]
This functionality is now implemented in the PEAR package PHP_Compat.
More information about using this function without upgrading your version of PHP can be found on the below link:
http://pear.php.net/package/PHP_Compat