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    override_function

    (PECL apd >= 0.2)

    override_function — Overrides built-in functions

    说明

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

    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;');
    ?>

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    User Contributed Notes 8 notes

    up
    94
    php at undeen dot com
    19 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
    17
    tothandor at gmail dot com
    10 years 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
    8
    alextoemail at gmail dot com
    9 years 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
    7
    Darien H
    10 years 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
    1
    boban dot acimovic at gmail dot com
    9 years 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
    0
    fran
    7 years ago
    You can find  Excepción - Call to undefined function override_function()
    due to Function override_function is part of PECL Extension.

    Configure PECL
    up
    -1
    pagan at o2 dot pl
    16 years ago
    There is not chance to override 2 or more functions, because of the error:
    Fatal error: Cannot redeclare __overridden__()
    up
    -3
    lange.ludo
    9 years ago
    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));
             /* CODE that manipulates the result */
             return $result;
    }
    ?>

    As a child :
    <?php
    function override_myFunction($arg,…,$argN)
    {        /* CODE that manipulates the arguments */
             return original_myFunction($arg,…,$argN));
    }
    ?>
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