Where to place global functions in codeigniter

As @david barker said, you might use an helper. Create a file named, for example, "site_helper", that contains all the functions.

be aware you need to check if the function already exists, though, or you'll get an "function already declared" error.

So, something like:

file site_helper.php (in application/helpers/ )

if(!function_exists('h')){  function h($value)  {   return htmlentities($value);  }}if(!functin_exists('other_function')//....etc.

And then you can autoload it in config/autoload.php:

$autoload['helpers'] = array('site');

^-- note how you only use the part before the underscore to call the file. Also, helpers are not classes, but a collection of functions.

You should include your global variables file in your /application/config/constants.php file. Then move your global function file to /application/helpers folder. Then you should autoload the global functions file. /application/config/autoload.php

$autoload['helpers'] = array('your-global-function-file.php');

I would suggest not moving anything inside of the system folder project, as upgrading would be an absolute nightmare. Sometimes refactoring your code to conform to CI logic, maybe faster in the long run rather than trying to copy/paste stuff all over the place.

This is exactly what Helpers are for.

Create a new helper (remember to append it with _helper.php) and put it in your helper folder.

You can either auto load it in your config (so you can use it anywhere), or just manually load it when needed.