"CURLINFO_EFFECTIVE_URL" - Last effective URL
"CURLINFO_HTTP_CODE" - Last received HTTP code
"CURLINFO_FILETIME" - Remote time of the retrieved document, if -1 is returned the time of the document is unknown
"CURLINFO_TOTAL_TIME" - Total transaction time in seconds for last transfer
"CURLINFO_NAMELOOKUP_TIME" - Time in seconds until name resolving was complete
"CURLINFO_CONNECT_TIME" - Time in seconds it took to establish the connection
"CURLINFO_PRETRANSFER_TIME" - Time in seconds from start until just before file transfer begins
"CURLINFO_STARTTRANSFER_TIME" - Time in seconds until the first byte is about to be transferred
"CURLINFO_REDIRECT_TIME" - Time in seconds of all redirection steps before final transaction was started
"CURLINFO_SIZE_UPLOAD" - Total number of bytes uploaded
"CURLINFO_SIZE_DOWNLOAD" - Total number of bytes downloaded
"CURLINFO_SPEED_DOWNLOAD" - Average download speed
"CURLINFO_SPEED_UPLOAD" - Average upload speed
"CURLINFO_HEADER_SIZE" - Total size of all headers received
"CURLINFO_HEADER_OUT" - The request string sent. Available since PHP 6.0.0
"CURLINFO_REQUEST_SIZE" - Total size of issued requests, currently only for HTTP requests
"CURLINFO_SSL_VERIFYRESULT" - Result of SSL certification verification requested by setting CURLOPT_SSL_VERIFYPEER
"CURLINFO_CONTENT_LENGTH_DOWNLOAD" - content-length of download, read from Content-Length: field
"CURLINFO_CONTENT_LENGTH_UPLOAD" - Specified size of upload
"CURLINFO_CONTENT_TYPE" - Content-type of downloaded object, NULL indicates server did not send valid Content-Type: header
If called without the optional parameter opt an associative array is returned with the following array elements which correspond to opt options: