Title: call_user_func_array expects parameter 1 to be a valid callback Last modified: August 30, 2016 --- # call_user_func_array expects parameter 1 to be a valid callback * [MailShark](https://wordpress.org/support/users/mailshark/) * (@mailshark) * [10 years, 11 months ago](https://wordpress.org/support/topic/call_user_func_array-expects-parameter-1-to-be-a-valid-callback-5/) * Hi, * Have recently installed wp-ffpc after installing and configuring a memcached server. * Using WP 4.2.2 on Debian with Apache2, PHP 5.4 and Xcache. * The errors we continually get are: * PHP Warning: call_user_func_array() expects parameter 1 to be a valid callback, function ‘wp_ffpc_redirect_callback’ not found or invalid function name in xxx/ wp-includes/plugin.php on line 213 * Searching the web it seems from this: * [http://stackoverflow.com/questions/25269636/wordpress-warning-call-user-func-array-expects-parameter-1-to-be-a-valid-call](http://stackoverflow.com/questions/25269636/wordpress-warning-call-user-func-array-expects-parameter-1-to-be-a-valid-call) * the fix is in the way the function is called from the wp_ffpc_redirect_callback? * Anyone know a fix for this? * Thanks. * [https://wordpress.org/plugins/wp-ffpc/](https://wordpress.org/plugins/wp-ffpc/) Viewing 4 replies - 1 through 4 (of 4 total) * [phil1984](https://wordpress.org/support/users/phil1984/) * (@phil1984) * [10 years, 11 months ago](https://wordpress.org/support/topic/call_user_func_array-expects-parameter-1-to-be-a-valid-callback-5/#post-6266286) * Hi MailShark * Please check your wp-content/advanced-cache.php file * Does it look ok? It should include the wp-ffpc-acache.php file at the end. If it doesn’t, try resaving in the settings page to regenerate the file. * Thanks * Thread Starter [MailShark](https://wordpress.org/support/users/mailshark/) * (@mailshark) * [10 years, 11 months ago](https://wordpress.org/support/topic/call_user_func_array-expects-parameter-1-to-be-a-valid-callback-5/#post-6266287) * Hi. Thank you for your reply, very much appreciated. * We have checked the advanced-cache.php and there is no reference to wp-ffpc-acache. php at all within the file. * Checking the advanced-cache.php file, it’s actually a file produced by WP SUPER CACHE 1.2 and comes from ./wp-content/plugins/wp-super-cache/advanced-cache.php, same size and all. * We went into WP-FFPC options and re-saved settings, the advanced-cache.php file remained the same though. No idea why WP-FFPC isn’t writing to the file. * Which wp-ffpc-acache.php line should be at the bottom of advanced-cache.php? maybe we can just add it manually? * Thanks. * [phil1984](https://wordpress.org/support/users/phil1984/) * (@phil1984) * [10 years, 11 months ago](https://wordpress.org/support/topic/call_user_func_array-expects-parameter-1-to-be-a-valid-callback-5/#post-6266288) * You cannot use both W3 Super cache and WP FFPC at the same time as they both hook in to wordpress using this file. * You cannot easily add it manually either because it needs all the settings you choose. * It is probably a file/directory permissions issue. The plugin will not update the advanced-cache.php file if it cannot remove it. Try deleting it through your ftp client. * The user who owns the server process (e.g. www or apache) needs to have write and execute permissions on the wp-content directory. You might need to make wp- content **group** writable and executable depending on which user owns the directory. * [xorbal](https://wordpress.org/support/users/xorbal/) * (@xorbal) * [10 years, 5 months ago](https://wordpress.org/support/topic/call_user_func_array-expects-parameter-1-to-be-a-valid-callback-5/#post-6266338) * Hi, * I recently started getting “Warning: call_user_func_array() expects parameter 1 to be a valid callback, array must have exactly two members in…” whenever I installed a plugin. I’m using WP 4.4 and php7. * Then I found this: [http://wordpress.stackexchange.com/questions/128864/getting-a-warning-call-user-func-array-error-whenever-i-install-update-a-pl](http://wordpress.stackexchange.com/questions/128864/getting-a-warning-call-user-func-array-error-whenever-i-install-update-a-pl) * After going through all WP-FFPC files, I found that commenting line 187 in wp- ffpc-class.php did the trick. * `//add_action( 'upgrader_process_complete', array ( &$this->plugin_upgrade ), 10, 2 );` * I guess I’ll just have to uncomment it to re-save settings after updating the plugin. * Anybody know a better way? * Thanks and happy new 2016! Viewing 4 replies - 1 through 4 (of 4 total) The topic ‘call_user_func_array expects parameter 1 to be a valid callback’ is closed to new replies. * ![](https://s.w.org/plugins/geopattern-icon/wp-ffpc_ffffff.svg) * [WP-FFPC](https://wordpress.org/plugins/wp-ffpc/) * [Frequently Asked Questions](https://wordpress.org/plugins/wp-ffpc/#faq) * [Support Threads](https://wordpress.org/support/plugin/wp-ffpc/) * [Active Topics](https://wordpress.org/support/plugin/wp-ffpc/active/) * [Unresolved Topics](https://wordpress.org/support/plugin/wp-ffpc/unresolved/) * [Reviews](https://wordpress.org/support/plugin/wp-ffpc/reviews/) * 4 replies * 3 participants * Last reply from: [xorbal](https://wordpress.org/support/users/xorbal/) * Last activity: [10 years, 5 months ago](https://wordpress.org/support/topic/call_user_func_array-expects-parameter-1-to-be-a-valid-callback-5/#post-6266338) * Status: not resolved