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CURLMOPT_PIPELINING(3) curl_multi_setopt options CURLMOPT_PIPELINING(3)
CURLMOPT_PIPELINING - enable HTTP pipelining and multiplexing
CURLMcode curl_multi_setopt(CURLM *handle, CURLMOPT_PIPELINING, long bitmask);
Pass in the bitmask parameter to instruct libcurl to enable HTTP
pipelining and/or HTTP/2 multiplexing for this multi handle.
When enabled, libcurl will attempt to use those protocol features when
doing parallel requests to the same hosts.
For pipelining, this means that if you add a second request that can
use an already existing connection, the second request will be "piped"
on the same connection rather than being executed in parallel.
For multiplexing, this means that follow-up requests can re-use an
existing connection and send the new request multiplexed over that at
the same time as other transfers are already using that single
There are several other related options that are interesting to tweak
and adjust to alter how libcurl spreads out requests on different
connections or not etc.
Before 7.43.0, this option was set to 1 and 0 to enable and disable
Starting in 7.43.0, bitmask's second bit also has a meaning, and you
can ask for pipelining and multiplexing independently of each other by
toggling the correct bits.
Default, which means doing no attempts at pipelining or
If this bit is set, libcurl will try to pipeline HTTP/1.1
requests on connections that are already established and in use
This bit is deprecated and has no effect since version 7.62.0.
If this bit is set, libcurl will try to multiplex the new
transfer over an existing connection if possible. This requires
Since 7.62.0, CURLPIPE_MULTIPLEX is enabled by default.
Before that, default was CURLPIPE_NOTHING.
CURLM *m = curl_multi_init();
/* try HTTP/2 multiplexing */
curl_multi_setopt(m, CURLMOPT_PIPELINING, CURLPIPE_MULTIPLEX);
Added in 7.16.0. Multiplex support bit added in 7.43.0. HTTP/1
Pipelining support was disabled in 7.62.0.
Returns CURLM_OK if the option is supported, and CURLM_UNKNOWN_OPTION
libcurl 7.87.0 October 19, 2022 CURLMOPT_PIPELINING(3)