Section: curl_multi_setopt options (3)
Updated: March 17, 2021
CURLMOPT_MAX_TOTAL_CONNECTIONS - max simultaneously open connections
CURLMcode curl_multi_setopt(CURLM *handle, CURLMOPT_MAX_TOTAL_CONNECTIONS, long amount);
Pass a long for the amount
. The set number will be used as the maximum
number of simultaneously open connections in total using this multi
handle. For each new session, libcurl will open a new connection up to the
limit set by CURLMOPT_MAX_TOTAL_CONNECTIONS(3)
. When the limit is
reached, the sessions will be pending until there are available
connections. If CURLMOPT_PIPELINING(3)
is enabled, libcurl will try to
use multiplexing if the host is capable of it.
When more transfers are added to the multi handle than what can be performed
due to the set limit, they will be queued up waiting for their chance. When
that happens, the CURLOPT_TIMEOUT_MS(3) timeout will be counted
inclusive of the waiting time, meaning that if you set a too narrow timeout in
such a case the transfer might never even start before it times out.
Even in the queued up situation, the CURLOPT_CONNECTTIMEOUT_MS(3)
timeout is however treated as a per-connect timeout.
The default value is 0, which means that there is no limit. It is then simply
controlled by the number of easy handles added.
CURLM *m = curl_multi_init();
/* never do more than 15 connections */
curl_multi_setopt(m, CURLMOPT_MAX_TOTAL_CONNECTIONS, 15L);
Added in 7.30.0
Returns CURLM_OK if the option is supported, and CURLM_UNKNOWN_OPTION if not.