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__halt_compiler

(PHP 5 >= 5.1.0, PHP 7, PHP 8)

__halt_compilerBeendet die Kompilerausführung

Beschreibung

__halt_compiler(): void

Beendet die Kompilerausführung. Dies kann sinnvoll sein, wenn Daten in PHP-Skripte eingebettet sind, wie z. B. in Installationsdateien.

Die Byteposition, an der die Daten beginnen, kann über die Konstante __COMPILER_HALT_OFFSET__ ermittelt werden, die nur definiert ist, wenn die Funktion __halt_compiler() in der Datei benutzt wird.

Parameter-Liste

Diese Funktion besitzt keine Parameter.

Rückgabewerte

Es wird kein Wert zurückgegeben.

Beispiele

Beispiel #1 Ein __halt_compiler()-Beispiel

<?php

// Datei öffnen
$fp = fopen(__FILE__, 'r');

// Auf den Anfang der Daten positionieren
fseek($fp, __COMPILER_HALT_OFFSET__);

// und diese ausgeben
var_dump(stream_get_contents($fp));

// hier Kompilation beenden
__halt_compiler(); ab hier die eigentlichen Daten (z.B. tar, gz, PHP, etc.)

Anmerkungen

Hinweis:

__halt_compiler() kann nur auf der höchsten Ausführungsebene und nicht innerhalb anderer Funktionen oder Methoden benutzt werden.

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User Contributed Notes 7 notes

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24
-T-
10 years ago
This function can be used in eval() -- it will halt the eval, but not the script eval"() was called in.
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15
ravenswd at gmail dot com
8 years 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.
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19
ravenswd at gmail dot com
13 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:

<?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
?>
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2
Krzysiek
9 years 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...
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1
joey at gimo dot co dot uk
9 years 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 ();.
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0
cwk32 at mail dot ustc dot edu dot cn
9 years 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 = =
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-2
alex at 1stleg dot com
4 years ago
Please note that __HALT_COMPILER() must be uppercase if used from a pharstub: https://www.php.net/manual/en/phar.fileformat.stub.php
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