Unlink function in php

Question

Is it possible to erase user-defined function?

My CMS has one function, which I want to update with additions.

Trying to add some code to theme's code, that would make my code work only when this theme is switched on.

Answer 1

Try rename_function() to rename the function you want to override to something else and then write the function under the original name.

Answer 2

Do not include or launch that code until the required theme is chosen.

My code for Default Theme from functions.php:

<?php
function sample()
{
    // the specific code here
}

Somewhere in the theme bootstrapping:

<?php
include 'functions.php';
sample();

// OR inside a theme.

if ($theme_name == 'default')
{
    // Call the function
    sample();
}