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| .TH CURLMOPT_PIPELINING 3 "November 04, 2020" "libcurl 7.78.0" "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\fP 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/2 multiplexing */ |
| curl_multi_setopt(m, CURLMOPT_PIPELINING, CURLPIPE_MULTIPLEX); |
| .fi |
| .SH AVAILABILITY |
| Added in 7.16.0. Multiplex support bit added in 7.43.0. HTTP/1 Pipelining |
| support was disabled in 7.62.0. |
| .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), " |
