override_function

(PECL apd >= 0.2)

override_function — Overrides built-in functions

说明

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

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

参数

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.

返回值

成功时返回 TRUE ，或者在失败时返回 FALSE 。

范例

Example #1 override_function() example

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

用户评论:

[#1] lange.ludo [2015-11-03 10:37:26]

Maybe it's better to use overwritten function inside the override to code something like this :
<?php rename_function('myFunction','original_myFunction'); override_function('myFunction','$arg,??,$argN','return override_myFunction($arg,??,$argN);'); ?>

You may then give somehow "inheritance" to override_myFunction ??
As a parent :
<?php function override_myFunction($arg,??,$argN) { $result=original_myFunction($arg,??,$argN)); return $result; } ?>

As a child :
<?php function override_myFunction($arg,??,$argN) { return original_myFunction($arg,??,$argN)); } ?>

[#2] alextoemail at gmail dot com [2015-09-04 21:47:04]

Of course you can't overwrite "functions" like require_once or print as they are not really a function but a language construct.

[#3] boban dot acimovic at gmail dot com [2015-01-14 12:30:18]

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');

[#4] tothandor at gmail dot com [2014-06-20 12:14:25]

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.

[#5] Darien H [2014-02-11 21:11:14]

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.

[#6] pagan at o2 dot pl [2008-10-24 00:34:05]

There is not chance to override 2 or more functions, because of the error:
Fatal error: Cannot redeclare __overridden__()

[#7] php at undeen dot com [2005-03-10 12:07:11]

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.