Adds a standard easy handle to the multi stack. This function call will make
this multi_handle control the specified easy_handle.
While an easy handle is added to a multi stack, you cannot and you must not
use curl_easy_perform(3) on that handle. After having removed the easy
handle from the multi stack again, it is perfectly fine to use it with the
easy interface again.
If the easy handle is not set to use a shared (CURLOPT_SHARE(3)) or
global DNS cache (CURLOPT_DNS_USE_GLOBAL_CACHE(3)), it will be made to
use the DNS cache that is shared between all easy handles within the multi
handle when curl_multi_add_handle(3) is called.
When an easy interface is added to a multi handle, it will use a shared
connection cache owned by the multi handle. Removing and adding new easy
handles will not affect the pool of connections or the ability to do
If you have CURLMOPT_TIMERFUNCTION set in the multi handle (and you really
should if youre working event-based with curl_multi_socket_action(3)
and friends), that callback will be called from within this function to ask
for an updated timer so that your main event loop will get the activity on
this handle to get started.
The easy handle will remain added to the multi handle until you remove it
again with curl_multi_remove_handle(3) - even when a transfer with that
specific easy handle is completed.
You should remove the easy handle from the multi stack before you terminate
first the easy handle and then the multi handle:
1 - curl_multi_remove_handle(3)
2 - curl_easy_cleanup(3)
3 - curl_multi_cleanup(3)