Title: Call to undefined function: add_filter()
Last modified: August 18, 2016

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# Call to undefined function: add_filter()

 *  [veronique-m](https://wordpress.org/support/users/veronique-m/)
 * (@veronique-m)
 * [20 years, 2 months ago](https://wordpress.org/support/topic/call-to-undefined-function-add_filter-2/)
 * strange. here i am again. would anybody know why the add_filter seems to be missing.
 * Fatal error: Call to undefined function: add_filter() in wp-content/plugins/character-
   map.php on line 1070
 * i’m trying to use striker’s Character Map plugin.
 * well, again, many thanks in advance for your kind answers.

Viewing 4 replies - 1 through 4 (of 4 total)

 *  [niziol](https://wordpress.org/support/users/niziol/)
 * (@niziol)
 * [20 years, 2 months ago](https://wordpress.org/support/topic/call-to-undefined-function-add_filter-2/#post-339870)
 * Well, not having any idea what the plugin is or does, I’d say it’s a “Call to
   an undefined function”.
 * Perhaps you could post some details, like the version of WordPress you’re using,
   a link to the plugin or the section of code that it references (ie: around 1070),
   make sure you use [pastebin](http://pastebin.com) to post any thing more than
   a line of code.
 * Once it’s up, then iut will be possible for someone to help you figure it out.
 * Good luck,
    Michael.
 *  Thread Starter [veronique-m](https://wordpress.org/support/users/veronique-m/)
 * (@veronique-m)
 * [20 years, 2 months ago](https://wordpress.org/support/topic/call-to-undefined-function-add_filter-2/#post-340151)
 * Michael,
 * The plugin was made by Skriker and can be found here : [http://fredfred.net/skriker/index.php/character-map](http://fredfred.net/skriker/index.php/character-map)
 * It’s a bit complicated for me to explain what it does in English. It opens a “
   character map” in an open window, where you can simply choose between all kinds
   of (weird but beautiful) character types.
 * As I asked him if he had a clue of what might be going wrong with my installation,
   the author of the plugin answered :
 * Yes, automatic detection of “stand-alone�? mode doesn’t work properly at your
   server…
 * Download the version 0.2 which has been improved in this detection.
 * [The problem is, i cannot install 0.2 on my server.](http://wordpress.org/support/topic/59365?replies=19)
   So it seems there’s no hope for me to use the plugin.
 * (By the way, could anybody explain to me what a “stand-alone” mode _means_.)
 * Thanks!
 * Véronique
 *  [niziol](https://wordpress.org/support/users/niziol/)
 * (@niziol)
 * [20 years, 2 months ago](https://wordpress.org/support/topic/call-to-undefined-function-add_filter-2/#post-340153)
 * Véronique,
 * I’d love to know what he means by stand-alone as well!
 * I’ve downloaded the plugin and will have a go at it, I’m not a programmer by 
   the stretcg of anyones imagination (not even my own), but sometimes I get lucky!
 * I know this isn’t ideal, but you can insert a lot of the characters that the 
   plugin can by using the alt key. For example, on my quest to learn Latin, I can
   use alt + 146 to add the AE ligature mark in my name, which produces:
 * MIHI•NOMEN•EST•MICHÆLVS
 * Hopefully it’s just a simple plugin issue and someone can figure it out! I tried
   the demo on his site and it certainly would be useful if it worked! I’ll post
   back here and let you know how it goes!
 * Cheers,
    Michael.
 *  [niziol](https://wordpress.org/support/users/niziol/)
 * (@niziol)
 * [20 years, 2 months ago](https://wordpress.org/support/topic/call-to-undefined-function-add_filter-2/#post-340170)
 * OK, I can’t even get the thing to anything, it only seems to show up on the plugin
   edit screen and when I deactivate it.
 * My guess is that it has something to do with the quicktag, seeing as how it does
   nothing at all, the button is there, but pressing it does nothing, either in 
   visual editor or the standard one.
 * From what I can gather, stand-alone mode is apparently just calling the script
   from the URI, which does call up the plugin interface, however, again, that’s
   about it – it doesn’t seem to do anything else.
 * Java is way over my head, I can’t even understand what this really does, nevermind
   why it doesn’t work. Sorry, I hope someone can figure this out, I’m very curious!
 * Good luck,
    Michael.

Viewing 4 replies - 1 through 4 (of 4 total)

The topic ‘Call to undefined function: add_filter()’ is closed to new replies.

## Tags

 * [add_filter](https://wordpress.org/support/topic-tag/add_filter/)
 * [server](https://wordpress.org/support/topic-tag/server/)
 * [stand-alone](https://wordpress.org/support/topic-tag/stand-alone/)

 * In: [Fixing WordPress](https://wordpress.org/support/forum/how-to-and-troubleshooting/)
 * 4 replies
 * 2 participants
 * Last reply from: [niziol](https://wordpress.org/support/users/niziol/)
 * Last activity: [20 years, 2 months ago](https://wordpress.org/support/topic/call-to-undefined-function-add_filter-2/#post-340170)
 * Status: not resolved

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