constants_curl_multi

CURLM_ADDED_ALREADY (int)
An easy handle already added to a multi handle was attempted to get added a second time. Available as of cURL 7.32.1.

CURLM_BAD_EASY_HANDLE (int)
An easy handle was not good/valid. It could mean that it is not an easy handle at all, or possibly that the handle already is in use by this or another multi handle. Available as of cURL 7.9.6.

CURLM_BAD_HANDLE (int)
The passed-in handle is not a valid multi handle. Available as of cURL 7.9.6.

CURLM_CALL_MULTI_PERFORM (int)
As of cURL 7.20.0, this constant is not used. Before cURL 7.20.0, this status could be returned by curl_multi_exec when curl_multi_select or a similar function was called before it returned any other constant. Available as of cURL 7.9.6.

CURLM_INTERNAL_ERROR (int)
Internal libcurl error. Available as of cURL 7.9.6.

CURLM_OK (int)
No errors. Available as of cURL 7.9.6.

CURLM_OUT_OF_MEMORY (int)
Ran out of memory while processing multi handles. Available as of cURL 7.9.6.