CURLOPT_PROGRESSFUNCTION

CURLOPT_PROGRESSFUNCTION is one of the accepted parameters for curl_setopt parameter #2.

CURLOPT_PROGRESSFUNCTION — A callback accepting five parameters. The first is the cURL resource, the second is the total number of bytes expected to be downloaded in this transfer, the third is the number of bytes downloaded so far, the fourth is the total number of bytes expected to be uploaded in this transfer, and the fifth is the number of bytes uploaded so far.

 Return a non-zero value to abort the transfer. In which case, the
 transfer will set a [`CURLE_ABORTED_BY_CALLBACK`](/codex/CURLE_ABORTED_BY_CALLBACK)
 error.

CURLOPT_PROGRESSFUNCTION = 20056;