如何用php下载文件？

         直接上代码：

function download_file($url = '', $fileName = '')
{
	$ch = curl_init();
	$fp = fopen($fileName, 'wb');
	curl_setopt($ch, CURLOPT_URL, $url);
	curl_setopt($ch, CURLOPT_FILE, $fp);
	curl_setopt($ch, CURLOPT_HEADER, 0);
	curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
	curl_setopt($ch, CURLOPT_TIMEOUT, 60);
	curl_exec($ch);
	curl_close($ch);
	fclose($fp);
}