WordPress at a glance
function is not described

SimplePie::set_file() public WP 1.0

Set an instance of SimplePie_File{} to use as a feed

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

No Hooks.

Return

true|false. True on success, false on failure

Usage

$SimplePie = new SimplePie();
$SimplePie->set_file( $file );
$file (required) (passed by reference — &)
-

Code of SimplePie::set_file() WP 5.7.2

<?php
public function set_file(&$file)
{
	if ($file instanceof SimplePie_File)
	{
		$this->feed_url = $file->url;
		$this->permanent_url = $this->feed_url;
		$this->file =& $file;
		return true;
	}
	return false;
}