.\" ************************************************************************** .\" * _ _ ____ _ .\" * Project ___| | | | _ \| | .\" * / __| | | | |_) | | .\" * | (__| |_| | _ <| |___ .\" * \___|\___/|_| \_\_____| .\" * .\" * Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al. .\" * .\" * This software is licensed as described in the file COPYING, which .\" * you should have received as part of this distribution. The terms .\" * are also available at https://curl.haxx.se/docs/copyright.html. .\" * .\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell .\" * copies of the Software, and permit persons to whom the Software is .\" * furnished to do so, under the terms of the COPYING file. .\" * .\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY .\" * KIND, either express or implied. .\" * .\" ************************************************************************** .\" .TH CURLMOPT_PIPELINING 3 "17 Jun 2014" "libcurl 7.37.0" "curl_multi_setopt options" .SH NAME CURLMOPT_PIPELINING \- enable HTTP pipelining and multiplexing .SH SYNOPSIS #include <curl/curl.h> CURLMcode curl_multi_setopt(CURLM *handle, CURLMOPT_PIPELINING, long bitmask); .SH DESCRIPTION Pass in the \fBbitmask\fP 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, \fBbitmask\fP's second bit also has a meaning, and you can ask for pipelining and multiplexing independently of each other by toggling the correct bits. .IP CURLPIPE_NOTHING (0) Default, which means doing no attempts at pipelining or multiplexing. .IP CURLPIPE_HTTP1 (1) 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. .IP CURLPIPE_MULTIPLEX (2) If this bit is set, libcurl will try to multiplex the new transfer over an existing connection if possible. This requires HTTP/2. .SH DEFAULT Since 7.62.0, \fBCURLPIPE_MULTIPLEX\bP is enabled by default. Before that, default was \fBCURLPIPE_NOTHING\fP. .SH PROTOCOLS HTTP(S) .SH EXAMPLE .nf CURLM *m = curl_multi_init(); /* try HTTP/1 pipelining and HTTP/2 multiplexing */ curl_multi_setopt(m, CURLMOPT_PIPELINING, CURLPIPE_HTTP1 | CURLPIPE_MULTIPLEX); .fi .SH AVAILABILITY Added in 7.16.0. Multiplex support bit added in 7.43.0. .SH RETURN VALUE Returns CURLM_OK if the option is supported, and CURLM_UNKNOWN_OPTION if not. .SH "SEE ALSO" .BR CURLMOPT_MAX_PIPELINE_LENGTH "(3), " .BR CURLMOPT_PIPELINING_SITE_BL "(3), " .BR CURLMOPT_CONTENT_LENGTH_PENALTY_SIZE "(3), " .BR CURLMOPT_CHUNK_LENGTH_PENALTY_SIZE "(3), " .BR CURLMOPT_MAX_HOST_CONNECTIONS "(3), " .BR CURLMOPT_MAXCONNECTS "(3), " .BR CURLMOPT_MAX_HOST_CONNECTIONS "(3), "