This function must be the last function to call for an easy session. It is the
opposite of the curl_easy_init(3) function and must be called with the
same handle as input that a curl_easy_init(3) call returned.
This might close all connections this handle has used and possibly has kept
open until now - unless it was attached to a multi handle while doing the
transfers. Dont call this function if you intend to transfer more files,
re-using handles is a key to good performance with libcurl.
Occasionally you may get your progress callback or header callback called from
within curl_easy_cleanup(3) (if previously set for the handle using
curl_easy_setopt(3)). Like if libcurl decides to shut down the
connection and the protocol is of a kind that requires a command/response
sequence before disconnect. Examples of such protocols are FTP, POP3 and IMAP.
Any use of the handle after this function has been called and have
returned, is illegal. curl_easy_cleanup(3) kills the handle and all
memory associated with it!
For libcurl versions before 7.17,: after youve called this function, you can
safely remove all the strings youve previously told libcurl to use, as it
wont use them anymore now.