Scott Reilly

Safely call a function, class method, or object method in a manner that doesn’t generate errors if those plugins cease to exist.
Various helper functions are provided that provide handy variations of this theme:
<ul>
<li><code>_sfc()</code>: Safely call a function and get its return value</li>
<li><code>_sfce()</code>: Safely call a function and echo its return value</li>
<li><code>_sfcf()</code>: Safely call a function; if it doesn’t exist, then a fallback function (if specified) is called</li>
<li><code>_sfcm()</code>: Safely call a function; if it doesn’t exist, then echo a message (if provided)</li>
</ul>
Let’s assume you had something like this in a template:
<pre><code><?php list_cities( 'Texas', 3 ); ?>
</code></pre>
If you deactivated the plugin that provided <code>list_cities()</code>, your site would generate an error when that template is accessed.
You can instead use <code>_sfc()</code>, which is provided by this plugin to call other functions, like so:
<pre><code><?php _sfc( 'list_cities', 'Texas', 3 ); ?>
</code></pre>
That will simply do nothing if the <code>list_cities()</code> function is not available.
If you’d rather display a message when the function does not exist, use <code>_sfcm()</code> instead, like so:
<pre><code><?php _sfcm( 'list_cities', 'The cities listing is temporarily disabled.', 'Texas', 3 ); ?>
</code></pre>
In this case, if <code>list_cities()</code> is not available, the text “The cities listing is temporarily disabled.” will be displayed.
If you’d rather call another function when the function does not exist, use _sfcf() instead, like so:
<pre><code><?php
 function unavailable_function_handler( $function_name ) { echo "The function $function_name is not available."; }
 _sfcf( 'nonexistent_function', 'unavailable_function_handler' );
?>
</code></pre>
In the event you want to safely call a function and echo its value, you can use <code>_sfce()</code> like so:
<pre><code><?php _sfce( 'largest_city', 'Tx' ); ?>
</code></pre>
Which is roughly equivalent to doing :
<pre><code><?php if function_exists( 'largest_city' ) { echo largest_city( 'Tx' ); } ?>
</code></pre>
<h4>Filter invocation method</h4>
To further prevent issues in your code should this plugin itself become deactivated, you can use indirect filter invocation to call the plugin functions. Each function has an associated filter with the same name as the function. Simply use <code>apply_filters()</code> to invoke that function instead of calling the function directly.
E.g. instead of:
<pre><code><?php _sfce( 'some_plugin_function_that_echoes', 'argument' ); ?>
</code></pre>
Do:
<pre><code><?php apply_filters( '_sfce', 'some_plugin_function_that_echoes', 'argument' ); ?>
</code></pre>
If you’re relying on the return value of a function and this plugin gets deactivated, note that the <code>apply_filters()</code> call will return the name of the function you intended to call, so you should check the return value to ensure the function got called.
Instead of:
<pre><code><?php $x = _sfc( 'some_plugin_function', 'argument' ); ?>
</code></pre>
Do:
<pre><code><?php
 $x = apply_filters( '_sfcq', 'some_plugin_function', 'argument' );
 if ( $x !== 'some_plugin_function' ) {
 // Work with the value of $x here.
 } else {
 // The Safe Function Call plugin isn't active.
 $x = 0; // Maybe set the variable to something that makes sense in this scenario.
 }
?>
</code></pre>
Links: <a href="https://coffee2code.com/wp-plugins/safe-function-call/" rel="nofollow ugc">Plugin Homepage</a> | <a href="https://wordpress.org/plugins/safe-function-call/" rel="ugc">Plugin Directory Page</a> | <a href="https://github.com/coffee2code/safe-function-call/" rel="nofollow ugc">GitHub</a> | <a href="https://coffee2code.com" rel="nofollow ugc">Author Homepage</a>
<h3>Developer Documentation</h3>
Developer documentation can be found in <a href="https://github.com/coffee2code/safe-function-call/blob/master/DEVELOPER-DOCS.md" rel="nofollow ugc">DEVELOPER-DOCS.md</a>. That documentation covers the template tags and hooks provided by the plugin.
As an overview, these are the template tags provided by the plugin:
<ul>
<li><code>_sfc()</code> : Safely call a function and get its return value.</li>
<li><code>_sfce()</code> : Safely call a function and echo its sanitized return value.</li>
<li><code>_sfcf()</code> : Safely call a function; if it doesn’t exist, then a fallback function (if specified) is called.</li>
<li><code>_sfcm()</code> : Safely call a function; if it doesn’t exist, then echo a message (if provided).</li>
</ul>
These are the hooks provided by the plugin. They are intended for filter invocation usage rather than typical content filtering.
<ul>
<li><code>_sfc</code> : Filter to safely invoke <code>_sfc()</code> in such a way that if the plugin were deactivated or deleted, then your calls to the function won’t cause errors in your site.</li>
<li><code>_sfce</code> : Filter to safely invoke <code>_sfce()</code> in such a way that if the plugin were deactivated or deleted, then your calls to the function won’t cause errors in your site.</li>
<li><code>_sfcf</code> : Filter to safely invoke <code>_sfcf()</code> in such a way that if the plugin were deactivated or deleted, then your calls to the function won’t cause errors in your site.</li>
<li><code>_sfcm</code> : Filter to safely invoke <code>_sfcm()</code> in such a way that if the plugin were deactivated or deleted, then your calls to the function won’t cause errors in your site.</li>
</ul>

Safe Function Call

Safely and easily call functions that may not be available (such as those provided by a plugin that gets deactivated)

Shamim Hasan

Lot of custom functions are ready to use. Just give a tick mark. Which one you tick only those functions will load. No extra css or js. Some of the functions are
<ul>
<li>Change amount of posts on the home page.</li>
<li>Change amount of posts on the search page.</li>
<li>Change length of excerpt.</li>
<li>Automatically mark as spam all comments with an url longer than set chars.</li>
<li>Set the post revisions unless the constant was set in wp-config.php already.</li>
<li>Control When Your Posts are Available via RSS.</li>
<li>Automatically empty trash after set days.</li>
<li>Change Admin footer.</li>
<li>Add favicon to head.</li>
<li>Remove unnecessary links from wp_head.</li>
<li>Redirect to home page after login.</li>
<li>Hide admin bar from front end for non admin.</li>
<li>Disable back end access for non admin users.</li>
<li>Login with both Email/username.</li>
<li>Show only own uploaded media in library.</li>
<li>Restrict user to upload only jpg,jpeg,png,gif type of media.</li>
<li>Stop images getting wrapped up in p tags when they get dumped out with the_content() for easier theme styling,</li>
<li>Call the google CDN version of jQuery for the frontend.</li>
<li>Call Googles HTML5 Shim, but only for users on old versions of IE.</li>
<li>Change login screen error messages to “Think you have gone wrong somwhere!”.</li>
<li>Show post thumbnail in RSS Feeds.</li>
<li>Disable RSS Feeds.</li>
<li>Display the Most Accurate Comment Count.</li>
<li>Custom admin menu link for all settings.</li>
<li>Enable admin to set custom background images in ‘appearance > background’.</li>
<li>Remove pings to self.</li>
<li>Sharpening resized jpg images.</li>
<li>Enable Gzip.</li>
<li>Prevent user email change from profile.</li>
<li>Block comments with no-referrer.</li>
<li>Remove word “Private: ” infront of title of private post/page.</li>
<li>Disable the theme/plugin editor in Admin.</li>
<li>Disallow anything that creates, deletes, or updates core, plugin, or theme files.</li>
<li>No more jumping for read more link.</li>
<li>Enable custom Breadcrumbs.</li>
<li>Disable Search in WordPress.</li>
<li>Disable Admin nag.</li>
<li>Remove wordpress version number.</li>
</ul>
For more details please visit <a href="http://www.banglardokan.com/blog/recent/project/custom-functions-plugin-2256/" rel="nofollow ugc">Custom Functions Plugin</a>

Custom Functions Plugin

No need any more functions.php file editing. Just give a tick mark and this plugin will do the rest for you.

Safe Function Call vs Custom Functions Plugin