Title: Safe Function Call Author: Scott Reilly Published: जून 11, 2009 Last modified: अप्रैल 14, 2025 --- Search plugins ![](https://ps.w.org/safe-function-call/assets/banner-772x250.png?rev=825360) ![](https://ps.w.org/safe-function-call/assets/icon-128x128.png?rev=972887) # Safe Function Call By [Scott Reilly](https://profiles.wordpress.org/coffee2code/) [Download](https://downloads.wordpress.org/plugin/safe-function-call.1.4.zip) * [Details](https://mai.wordpress.org/plugins/safe-function-call/#description) * [Reviews](https://mai.wordpress.org/plugins/safe-function-call/#reviews) * [Installation](https://mai.wordpress.org/plugins/safe-function-call/#installation) * [Development](https://mai.wordpress.org/plugins/safe-function-call/#developers) [Support](https://wordpress.org/support/plugin/safe-function-call/) ## Description 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: * `_sfc()`: Safely call a function and get its return value * `_sfce()`: Safely call a function and echo its return value * `_sfcf()`: Safely call a function; if it doesn’t exist, then a fallback function( if specified) is called * `_sfcm()`: Safely call a function; if it doesn’t exist, then echo a message ( if provided) Let’s assume you had something like this in a template: ``` ``` If you deactivated the plugin that provided `list_cities()`, your site would generate an error when that template is accessed. You can instead use `_sfc()`, which is provided by this plugin to call other functions, like so: ``` ``` That will simply do nothing if the `list_cities()` function is not available. If you’d rather display a message when the function does not exist, use `_sfcm()` instead, like so: ``` ``` In this case, if `list_cities()` 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: ``` ``` In the event you want to safely call a function and echo its value, you can use ` _sfce()` like so: ``` ``` Which is roughly equivalent to doing : ``` ``` #### Filter invocation method 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 `apply_filters()` to invoke that function instead of calling the function directly. E.g. instead of: ``` ``` Do: ``` ``` If you’re relying on the return value of a function and this plugin gets deactivated, note that the `apply_filters()` 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: ``` ``` Do: ``` ``` Links: [Plugin Homepage](https://coffee2code.com/wp-plugins/safe-function-call/) | [Plugin Directory Page](https://wordpress.org/plugins/safe-function-call/) | [GitHub](https://github.com/coffee2code/safe-function-call/) | [Author Homepage](https://coffee2code.com) ### Developer Documentation Developer documentation can be found in [DEVELOPER-DOCS.md](https://github.com/coffee2code/safe-function-call/blob/master/DEVELOPER-DOCS.md). That documentation covers the template tags and hooks provided by the plugin. As an overview, these are the template tags provided by the plugin: * `_sfc()` : Safely call a function and get its return value. * `_sfce()` : Safely call a function and echo its sanitized return value. * `_sfcf()` : Safely call a function; if it doesn’t exist, then a fallback function( if specified) is called. * `_sfcm()` : Safely call a function; if it doesn’t exist, then echo a message ( if provided). These are the hooks provided by the plugin. They are intended for filter invocation usage rather than typical content filtering. * `_sfc` : Filter to safely invoke `_sfc()` 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. * `_sfce` : Filter to safely invoke `_sfce()` 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. * `_sfcf` : Filter to safely invoke `_sfcf()` 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. * `_sfcm` : Filter to safely invoke `_sfcm()` 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. ## Installation 1. Install via the built-in WordPress plugin installer. Or download and unzip `safe- function-call.zip` inside the plugins directory for your site (typically `wp-content/ plugins/`) 2. Activate the plugin through the ‘Plugins’ admin menu in WordPress 3. Use any of the four functions provided by this plugin as desired ## FAQ ### Do the functions provided by this plugin capture any error messages generated by the specified function? No. ### Why would I use any of these functions instead of using `function_exists()`/`method_exists()` directly? The functions provided by this plugin provide a more concise syntax for checking for function existence (but they do use `function_exists()`/`method_exists()` under the hood). `_sfce()` will both echo and return the echoed value, which may be of use in certain circumstances. And also, since the callback to be safely called is passed as an argument, it can be easily and more concisely parameterized. ### Won’t the problems this plugin addresses become a problem when using this plugin if it itself gets deactivated? Yes, if you make direct use of one of this plugin’s functions and then deactivate the plugin, you will likely encounter an error. However, if you make use indirect filter invocation, you can prevent errors. See the “Filter invocation method” section of the extended plugin description for example code. ### Does this plugin include unit tests? Yes. The tests are not packaged in the release .zip file or included in plugins. svn.wordpress.org, but can be found in the [plugin’s GitHub repository](https://github.com/coffee2code/safe-function-call/). ## Reviews ![](https://secure.gravatar.com/avatar/b553ddfd3593f64cda4b436e9f839c31c6cf29fea457be2a42b64b6373252ec6? s=60&d=retro&r=g) ### 󠀁[Works perfectly.](https://wordpress.org/support/topic/works-perfectly-1014/)󠁿 [Noahj Champion](https://profiles.wordpress.org/noahj-champion/) जनवरी 11, 2017 Works perfectly and offers enough fallback context to be very useful in theme development, especially themes or plugins which are designed for developers to extend. Thank you. [ Read all 1 review ](https://wordpress.org/support/plugin/safe-function-call/reviews/) ## Contributors & Developers “Safe Function Call” is open source software. The following people have contributed to this plugin. Contributors * [ Scott Reilly ](https://profiles.wordpress.org/coffee2code/) [Translate “Safe Function Call” into your language.](https://translate.wordpress.org/projects/wp-plugins/safe-function-call) ### Interested in development? [Browse the code](https://plugins.trac.wordpress.org/browser/safe-function-call/), check out the [SVN repository](https://plugins.svn.wordpress.org/safe-function-call/), or subscribe to the [development log](https://plugins.trac.wordpress.org/log/safe-function-call/) by [RSS](https://plugins.trac.wordpress.org/log/safe-function-call/?limit=100&mode=stop_on_copy&format=rss). ## Changelog #### 1.4 (2025-04-09) Highlights: This minor release sanitizes the output of the callback return value in `_sfce()` and the `$msg_if_missing` argument value to `_sfce()`, notes compatibility through WP 6.8+ and PHP 8.3+, and updates copyright date (2025). Details: * Hardening: Sanitize output of callback return value in `_sfce()` * Hardening: Sanitize output of `$msg_if_missing` argument value to `_sfcm()` * Change: Note compatibility through WP 6.8+ * Change: Note compatibility through PHP 8.3+ * Change: Update copyright date (2025) #### 1.3.3 (2024-08-09) * Change: Note compatibility through WP 6.6+ * Change: Update copyright date (2024) * New: Add `.gitignore` file * Change: Remove development and testing-related files from release packaging * Unit tests: - Hardening: Prevent direct web access to `bootstrap.php` - Allow tests to run against current versions of WordPress - New: Add `composer.json` for PHPUnit Polyfill dependency - Change: In bootstrap, store path to plugin directory in a constant #### 1.3.2 (2023-05-19) * New: Add DEVELOPER-DOCS.md and move hooks documentation into it * New: Add TODO.md with potential TODO items * Change: Improve some inline documentation formatting * Change: Note compatibility through WP 6.3+ * Change: Update copyright date (2023) #### 1.3.1 (2021-09-26) * Change: Note compatibility through WP 5.8+ * Unit tests: - Change: Restructure unit test directories * Change: Move `phpunit/bin/` into `tests/` * Change: Move `phpunit/` into `tests/` - Change: Remove ‘test-‘ prefix from unit test file - Change: In bootstrap, store path to plugin file constant - Change: In bootstrap, add backcompat for PHPUnit pre-v6.0 _Full changelog is available in [CHANGELOG.md](https://github.com/coffee2code/safe-function-call/blob/master/CHANGELOG.md)._ ## Meta * Version **1.4** * Last updated **12 months ago** * Active installations **10+** * WordPress version ** 1.5 or higher ** * Tested up to **6.8.5** * Language * [English (US)](https://wordpress.org/plugins/safe-function-call/) * Tags * [coffee2code](https://mai.wordpress.org/plugins/tags/coffee2code/)[error](https://mai.wordpress.org/plugins/tags/error/) [function](https://mai.wordpress.org/plugins/tags/function/)[template](https://mai.wordpress.org/plugins/tags/template/) * [Advanced View](https://mai.wordpress.org/plugins/safe-function-call/advanced/) ## Ratings 5 out of 5 stars. * [ 1 5-star review ](https://wordpress.org/support/plugin/safe-function-call/reviews/?filter=5) * [ 0 4-star reviews ](https://wordpress.org/support/plugin/safe-function-call/reviews/?filter=4) * [ 0 3-star reviews ](https://wordpress.org/support/plugin/safe-function-call/reviews/?filter=3) * [ 0 2-star reviews ](https://wordpress.org/support/plugin/safe-function-call/reviews/?filter=2) * [ 0 1-star reviews ](https://wordpress.org/support/plugin/safe-function-call/reviews/?filter=1) [Your review](https://wordpress.org/support/plugin/safe-function-call/reviews/#new-post) [See all reviews](https://wordpress.org/support/plugin/safe-function-call/reviews/) ## Contributors * [ Scott Reilly ](https://profiles.wordpress.org/coffee2code/) ## Support Got something to say? Need help? [View support forum](https://wordpress.org/support/plugin/safe-function-call/) ## Donate Would you like to support the advancement of this plugin? [ Donate to this plugin ](https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=6ARCFJ9TX3522)