DragonFly On-Line Manual Pages
CURLMOPT_MAX_HOST_CONNECTIONS(3) curl_multi_setopt options
CURLMOPT_MAX_HOST_CONNECTIONS - set max number of connections to a
CURLMcode curl_multi_setopt(CURLM *handle,
CURLMOPT_MAX_HOST_CONNECTIONS, long max);
Pass a long to indicate max. The set number will be used as the maximum
amount of simultaneously open connections to a single host (a host
being the same as a host name + port number pair). For each new session
to a host, libcurl will open a new connection up to the limit set by
CURLMOPT_MAX_HOST_CONNECTIONS(3). When the limit is reached, the
sessions will be pending until a connection becomes available. If
CURLMOPT_PIPELINING(3) is enabled, libcurl will try to pipeline if the
host is capable of it.
The default max value is 0, unlimited. However, for backwards
compatibility, setting it to 0 when CURLMOPT_PIPELINING(3) is 1 will
not be treated as unlimited. Instead it will open only 1 connection and
try to pipeline on it.
This set limit is also used for proxy connections, and then the proxy
is considered to be the host for which this limit counts.
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.
CURLM *m = curl_multi_init();
/* do no more than 2 connections per host */
curl_multi_setopt(m, CURLMOPT_MAX_HOST_CONNECTIONS, 2L);
Added in 7.30.0
Returns CURLM_OK if the option is supported, and CURLM_UNKNOWN_OPTION
libcurl 7.76.0 March 17, 2021