NAME

       CURLMOPT_PIPELINING - enable HTTP pipelining and multiplexing

SYNOPSIS

       #include <curl/curl.h>

       CURLMcode curl_multi_setopt(CURLM *handle, CURLMOPT_PIPELINING, long bitmask);

DESCRIPTION

       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 connection.

       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 HTTP/1.1 pipelining.

       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.

       CURLPIPE_NOTHING
       Default, which means doing no attempts at pipelining or multiplexing.

       CURLPIPE_HTTP1
        If  this  bit  is set, libcurl will try to pipeline HTTP/1.1 requests on connections that
        are already established and in use to hosts.

        This bit is deprecated and has no effect since version 7.62.0.

       CURLPIPE_MULTIPLEX
         If this bit is set, libcurl will try to multiplex the  new  transfer  over  an  existing
         connection if possible. This requires HTTP/2.

DEFAULT

       Since 7.62.0, CURLPIPE_MULTIPLEX is enabled by default.

       Before that, default was CURLPIPE_NOTHING.

PROTOCOLS

       HTTP(S)

EXAMPLE

       CURLM *m = curl_multi_init();
       /* try HTTP/2 multiplexing */
       curl_multi_setopt(m, CURLMOPT_PIPELINING, CURLPIPE_MULTIPLEX);

AVAILABILITY

       Added  in  7.16.0.  Multiplex  support  bit added in 7.43.0. HTTP/1 Pipelining support was
       disabled in 7.62.0.

RETURN VALUE

       Returns CURLM_OK if the option is supported, and CURLM_UNKNOWN_OPTION if not.

SEE ALSO

       CURLMOPT_MAX_PIPELINE_LENGTH(3),                           CURLMOPT_PIPELINING_SITE_BL(3),
       CURLMOPT_CONTENT_LENGTH_PENALTY_SIZE(3),            CURLMOPT_CHUNK_LENGTH_PENALTY_SIZE(3),
       CURLMOPT_MAXCONNECTS(3), CURLMOPT_MAX_HOST_CONNECTIONS(3),