PHP 7.0.6 Released


(PHP 5 >= 5.1.0, PHP 7)

__halt_compiler Halts the compiler execution


void __halt_compiler ( void )

Halts the execution of the compiler. This can be useful to embed data in PHP scripts, like the installation files.

Byte position of the data start can be determined by the __COMPILER_HALT_OFFSET__ constant which is defined only if there is a __halt_compiler() presented in the file.

Return Values

No value is returned.


Example #1 A __halt_compiler() example


// open this file
$fp fopen(__FILE__'r');

// seek file pointer to data

// and output it

// the end of the script execution
__halt_compiler(); the installation data (egtargzPHPetc.)



__halt_compiler() can only be used from the outermost scope.

User Contributed Notes

2 years ago
What zsh mentioned six years ago: "Also, it cannot be used in eval() -- it won't throw a syntax error, but it won't do anything either." is wrong. It can be used in eval() -- it will halt the eval.
cwk32 at mail dot ustc dot edu dot cn
1 year ago
if you find the value of __COMPILER_HALT_OFFSET__ is highly strange. Maybe...

there are some complier optimization tools, like eAccelator(very old). When the program is pre-complied and cached, the __COMPILER_HALT_OFFSET__ will be 0 = =
1 year ago
Joey, you're wrong saying that __halt_compiler have strange behavior. This structure works exactly the same as any other build in structure like empty or isset (even similarly to functions; at least in tokenizer level).

About T_OPEN_TAG - after one open tag is present you didn't expect other one in current php code section, so tokenizer try to handle this "thing" in other way and it's perfectly normal...
joey at gimo dot co dot uk
1 year ago
I don't exactly know what PHP is doing internally but I don't understand the sanity behind how in token_get_all __halt_compiler is handled.

This is actually valid there:
__halt_compiler/**/ /**/ /**/ /**/ /** */();raw

Normally it pops off just any three tokens so you can have even __halt_compiler***, __halt_compiler))), etc in token _get all.

The weird thing is that is also skips T_OPEN_TAG but in the context __halt_compiler runs in this tag should not be posible. Instead it will pick up < and ? as operators and php as a T_STRING.

It ignores the token at any point so this is also valid:
__halt_compiler()/**/ /**/ /**/ /**/ /** */;raw

When I test this with a php file rather than the tokeniser it works the same.

I can only conclude that PHP/__halt_compiler is pretty weird.

I think this is from attempting to weakly imitate the same syntax handling as in functions (I guess you can put comments/whitespace anywhere). I find it annoying and counter productive though.

Even this is valid:
__halt_compiler// comment\n();raw

A general problem that compound matters is that tokenise wont check whether or not syntax is valid (tokens against each other). When running as PHP you must have ();.
ravenswd at gmail dot com
5 years ago
__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:

if ( $something ):
// endif placed here for debugging purposes
// original location of endif -- would produce syntax error if __halt_compiler was not there
ravenswd at gmail dot com
2 months ago
If "__halt_compiler();" appears in a file which is "include"d or "require"d, then the called-in file will be treated as if it physically cuts off at the "__halt_compiler();". In other words, "__halt_compiler();" only affects the physical file it's in, an outer file that pulls it in will continue to execute.
8 years ago
__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.
2 years ago
This is not what people expect to see on manual pages, don't take this as example.
Ultimater at gmail dot com
6 years ago
Another possible usage, in addition to binary data and installers,
is using it to separate model, view and controller logic from one another:

class viewhelper{function render(){

//database logic goes here
//database logic goes here

//controller logic goes here
$view=new viewhelper;
$view->title="Test -> Ultimater's MVC example";
//controller logic goes here

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
<html xmlns="">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<style type="text/css">
<td>Hello <a href="<?=$this->base?>/showuser.php?id=<?=$this->userid?>
<td><a href="<?=$this->base?>/logout.php">Log Out</a></td>
<th><a href="<?=$this->base?>/usercp.php">UserCP</a></th>
<? if($this->authbar->modcp){ ?>
<td>&middot;</td><th><a href="<?=$this->base?>/modcp.php">ModCP</a></th>
<? } ?>
<? if($this->authbar->admincp){ ?>
<td>&middot;</td><th><a href="<?=$this->base?>/admincp.php">AdminCP</a></th>
<? } ?>
<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>
<? } ?>
To Top