How can I call a function from one plugin within another plugin?

I have a basic plugin in the admin options panel for events.

I want to call a function that is from a different social media plugin (Mingle). I can call the plugin functions in the theme, but not within core files of other plugins, or other plugins’ admin panels it seems.

I have tried including the other plugin’s files, adding a hook to the theme functions file, add_action, add_filter, init etc. But I do not know what the first argument for those actions would be, since I want the function inserted into a specific admin page from another plugin.

The only solution that has worked is merging the code of the two plugins, although it seems odd that there is not a simpler method.

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Maybe you should try calling the functions of your plugin using the plugins_loaded action.

Plugin A

class PluginA {
  public function func_a() {
    // do stuff

Plugin B

class PluginB {
  function functB() {
    if (class_exists('PluginA')) {
      //do stuff that depends of PluginA

add_action('plugins_loaded', 'call_plugin_a_using_plugin_b');
function call_plugin_a_using_plugin_b() {

According to the Codex, the plugins_loaded action fires after all plugins are loaded, so making sure that all plugins are loaded before calling a function from other plugin might be the way to go.

To call one function from one plugin in another plugin (inception?), you can try the following login:

You can try by checking for the function you want before doing anything else.

Plugin A:

function from_plugin_alpha( some_thing ) {
    // do stuff

Plugin B:

function from_plugin_bravo() {
    if ( !function_exists( 'from_plugin_alpha' ) ) {
    from_plugin_alpha( some_thing );

This checks that function exists before executing your custom code.