PHP 5.4.45 Released

override_function

(PECL apd >= 0.2)

override_functionOverrides built-in functions

Beschreibung

bool override_function ( string $function_name , string $function_args , string $function_code )

Overrides built-in functions by replacing them in the symbol table.

Parameter-Liste

function_name

The function to override.

function_args

The function arguments, as a comma separated string.

Usually you will want to pass this parameter, as well as the function_code parameter, as a single quote delimited string. The reason for using single quoted strings, is to protect the variable names from parsing, otherwise, if you use double quotes there will be a need to escape the variable names, e.g. \$your_var.

function_code

The new code for the function.

Rückgabewerte

Gibt bei Erfolg TRUE zurück. Im Fehlerfall wird FALSE zurückgegeben.

Beispiele

Beispiel #1 override_function() example

<?php
override_function
('test''$a,$b''echo "DOING TEST"; return $a * $b;');
?>

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User Contributed Notes 6 notes

up
36
php at undeen dot com
10 years ago
I thought the example was not very helpful, because it doesn't even override the function with another function.
My question was: If I override a function, can I call the ORIGINAL function within the OVERRIDING function?
ie, can I do this:
<?php
override_function
('strlen', '$string', 'return override_strlen($string);');
function
override_strlen($string){
        return
strlen($string); 
}
?>
The answer: NO, you will get a segfault.

HOWEVER, if you use rename_function to rename the original function to a third name, then call the third name in the OVERRIDING function, you will get the desired effect:
<?php
rename_function
('strlen', 'new_strlen');
override_function('strlen', '$string', 'return override_strlen($string);');

function
override_strlen($string){
        return
new_strlen($string); 
}
?>

I plan to use this functionality to generate log reports every time a function is called, with the parameters, time, result, etc... So to wrap a function in logging, that was what I had to do.
up
6
tothandor at gmail dot com
1 year ago
Overriden function name becomes __overridden__(). That's why you can't override two function, and that's how you can use the original function in the override.
up
5
Darien H
1 year ago
Please note that this function (as of v1.0.1 in PHP 5.3) will <b>not</b> override some important built-in "functions". Specifically, those which are actually statements/keywords, such as:

    require
    include
    require_once
    include_once
    echo
    print

I was hoping to use it to trace the chains of require/include activity among files in a large legacy project, but it seems APD will not do what I need.
up
0
alextoemail at gmail dot com
8 hours ago
Of course you can't overwrite "functions" like require_once or print as they are not really a function but a language construct.
up
0
boban dot acimovic at gmail dot com
7 months ago
Yes you can if you rename the overridden function. So you first rename original function, then override it and finally rename the overridden one, something like this:

rename_function('feof', 'real_feof');
override_function('feof', '$handle', 'return true;');
rename_function("__overridden__", 'dummy_feof');
up
-1
pagan at o2 dot pl
6 years ago
There is not chance to override 2 or more functions, because of the error:
Fatal error: Cannot redeclare __overridden__()
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