使用PHP转义CURL @符号

$curl = curl_init();
curl_setopt($curl, CURLOPT_URL, "http://example.com/upload.php");
curl_setopt($curl, CURLOPT_POST, 1);
curl_setopt($curl, CURLOPT_POSTFIELDS, array(
    'file' => '@' . realpath('path/to/file.txt')
));
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);

$result = curl_exec($curl);
curl_close($curl);