WordPress at a glance
function is not described

WC_Logger::add() public WC 1.0

Add a log entry.

This is not the preferred method for adding log messages. Please use log() or any one of the level methods (debug(), info(), etc.). This method may be deprecated in the future.

{} It's a method of the class: WC_Logger{}

Hooks from the method
Return

true|false. Nothing.

Usage

$WC_Logger = new WC_Logger();
$WC_Logger->add( $handle, $message, $level );
$handle(string) (required)
File handle.
$message(string) (required)
Message to log.
$level(string)
Logging level.

Code of WC_Logger::add() WC 5.3.0

<?php
public function add( $handle, $message, $level = WC_Log_Levels::NOTICE ) {
	$message = apply_filters( 'woocommerce_logger_add_message', $message, $handle );
	$this->log(
		$level,
		$message,
		array(
			'source'  => $handle,
			'_legacy' => true,
		)
	);
	wc_do_deprecated_action( 'woocommerce_log_add', array( $handle, $message ), '3.0', 'This action has been deprecated with no alternative.' );
	return true;
}