wp-includes/class-wp-hook.php:299Calls the callback functions that have been added to a filter hook.
$valuemixed$argsarraymixed public function apply_filters( $value, $args ) { if ( ! $this->callbacks ) { return $value; } $nesting_level = $this->nesting_level++; $this->iterations[ $nesting_level ] = $this->priorities; $num_args = count( $args ); do { $this->current_priority[ $nesting_level ] = current( $this->iterations[ $nesting_level ] ); $priority = $this->current_priority[ $nesting_level ]; foreach ( $this->callbacks[ $priority ] as $the_ ) { if ( ! $this->doing_action ) { $args[0] = $value; } // Avoid the array_slice() if possible. if ( 0 === $the_['accepted_args'] ) { $value = call_user_func( $the_['function'] ); } elseif ( $the_['accepted_args'] >= $num_args ) { $value = call_user_func_array( $the_['function'], $args ); } else { $value = call_user_func_array( $the_['function'], array_slice( $args, 0, $the_['accepted_args'] ) ); } } } while ( false !== next( $this->iterations[ $nesting_level ] ) ); unset( $this->iterations[ $nesting_level ] ); unset( $this->current_priority[ $nesting_level ] ); --$this->nesting_level; return $value; }Introduced in 4.7.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/class-wp-hook.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.