I am working on creating a filter module starting with the hook_filter_info file. This hook requires a callback method via a 'process callback' filter setting.

Now the problem is: how do I know what parameters that this callback method requires? I have taken a look at filter.api.php and see this:

function hook_filter_FILTER_process($text, $filter, $format, $langcode, $cache, $cache_id)      {
$text = preg_replace('|\[codefilter_code\](.+?)\[/codefilter_code\]|se', "<pre>$1</pre>", $text);
return $text;

but I have seen this callback filter called like this :

mymodule_process($text, $filter, $format);

mymodule_process($text, $filter, $format, $language);

mymodule_process($text, $filter, $format, $language, $cache);


Now how do I know the amount of arguments that this method requires? Or does it require any argument at all?


I've never had to use this specific hook before, but I have found a breakdown of the callback in the Drupal docs:


Pretty sure everything you're after will be described in the documentation. You can view all the other Filter API functions within the documentation here:


  • i have read the documentation and i see the number of parameters but if you look at my question, i am asking about the function signature. We can pretty much call it with any number of parameters and we are not getting any errors. – winteck Feb 16 '14 at 15:25

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