WP_Widget::_register_one( int $number = -1 )

Source

File: wp-includes/class-wp-widget.php

public function _register_one( $number = -1 ) {
		wp_register_sidebar_widget(
			$this->id,
			$this->name,
			$this->_get_display_callback(),
			$this->widget_options,
			array( 'number' => $number )
		);

		_register_widget_update_callback(
			$this->id_base,
			$this->_get_update_callback(),
			$this->control_options,
			array( 'number' => -1 )
		);

		_register_widget_form_callback(
			$this->id,
			$this->name,
			$this->_get_form_callback(),
			$this->control_options,
			array( 'number' => $number )
		);
	}