(PHP 5 >= 5.1.0)
__halt_compiler — 中断编译器的执行
中断编译器的执行。常用于在PHP脚本内嵌入数据，类似于安装文件。
可以通过常量 __COMPILER_HALT_OFFSET__ 获取数据开始字节所在的位置，且该常量仅被定义于使用了__halt_compiler的文件。
没有返回值。
Example #1 A __halt_compiler() 例子
<?php
// open this file
$fp = fopen(__FILE__, 'r');
// seek file pointer to data
fseek($fp, __COMPILER_HALT_OFFSET__);
// and output it
var_dump(stream_get_contents($fp));
// the end of the script execution
__halt_compiler(); the installation data (eg. tar, gz, PHP, etc.)
Note:
__halt_compiler() 仅能够在最外层使用。
mael d0t nison 47 epitech d0t net (2010-11-17 07:06:21)
It's possible to use __halt_compiler() with included files.
Only the current file will be affected, so it could be a good way to make plugins which embed a controller and its view in the same file (like Ultimater at gmail dot com did).
Base.php
<?php
echo "Base 1\n";
require 'Included.php';
echo "Base2 \n";
?>
Included.php
<?php
echo "Included 1\n";
__halt_compiler();
echo "Included 2\n";
?>
Calling Base.php will display:
Base 1
Included 1
Base 2
ravenswd at gmail dot com (2010-06-29 06:16:19)
__halt_compiler is also useful for debugging. If you need to temporarily make a change that will introduce an error later on, use __halt_compiler to prevent syntax errors. For example:
<?php
if ( $something ):
print 'something';
endif; // endif placed here for debugging purposes
__halt_compiler();
endif; // original location of endif -- would produce syntax error if __halt_compiler was not there
?>
Ultimater at gmail dot com (2009-05-14 06:36:18)
Another possible usage, in addition to binary data and installers,
is using it to separate model, view and controller logic from one another:
<?php
class viewhelper{function render(){
eval(file_get_contents(__FILE__,null,null,__COMPILER_HALT_OFFSET__));
}}
//database logic goes here
$row=array(
'loggedin'=>true,
'modcp'=>true,
'admincp'=>false,
'username'=>'Ultimater',
'userid'=>1234
);
//database logic goes here
//controller logic goes here
$view=new viewhelper;
$view->title="Test -> Ultimater's MVC example";
$view->base="http://".$_SERVER['HTTP_HOST'];
$view->username=$row['username'];
$view->userid=$row['userid'];
$view->authbar->loggedin=$row['loggedin'];
$view->authbar->modcp=$row['modcp'];
$view->authbar->admincp=$row['admincp'];
$view->render();
//controller logic goes here
__halt_compiler();?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title><?=htmlentities($this->title)?></title>
<style type="text/css">
a{color:#3333ff;text-decoration:none;}
a:hover{color:#0380fc;}
</style>
</head>
<body>
<?php
if($this->authbar->loggedin){
?>
<table><tr>
<td>Hello <a href="<?=$this->base?>/showuser.php?id=<?=$this->userid?>
"><?=htmlentities($this->username)?></a></td><td>[</td>
<td><a href="<?=$this->base?>/logout.php">Log Out</a></td>
<th><a href="<?=$this->base?>/usercp.php">UserCP</a></th>
<? if($this->authbar->modcp){ ?>
<td>·</td><th><a href="<?=$this->base?>/modcp.php">ModCP</a></th>
<? } ?>
<? if($this->authbar->admincp){ ?>
<td>·</td><th><a href="<?=$this->base?>/admincp.php">AdminCP</a></th>
<? } ?>
<td>]</td>
</tr></table>
<?php
}else{
?>
<table><tr><td>Hello Guest</td><td>[</td>
<td><a href="<?=$this->base?>/login.php">Log In</a></td>
<th><a href="<?=$this->base?>/register.php">Register</a></th>
<td>]</td></tr></table>
<? } ?>
</body>
</html>
gn_shallyNOSPAM at yahoo dot com (2008-06-03 19:56:19)
actually, __halt_compiler did something, even in eval function, that things is set the constant __COMPILER_HALT_OFFSET__ to the right value
as all of you might know, PHP will change content of some magic constant like __FUNCTION__, __CLASS__, etc based on the situation. so do the __COMPILER_HALT_OFFSET__ constant, is a file specific constant, just like the __FILE__ constant, the content will be changed based on wich file the __halt_compiler() reside.
try this:
/**** whatever.php ****/
<?php
eval('echo __FILE__."(".__COMPILER_HALT_OFFSET__.")\n"; __halt_compiler();');
echo __FILE__."(".__COMPILER_HALT_OFFSET__.")\n"; __halt_compiler();
if (!isset($whatever))
{
$whatever = 'whatever';
include __FILE__;
}
__halt_compiler();whatever
zsh (2007-10-12 04:11:58)
__halt_compiler() is a language construct and therefore cannot be used as a variable function.
Also, it cannot be used in eval() -- it won't throw a syntax error, but it won't do anything either.