curl/docs/libcurl/opts/CURLMOPT_PIPELINING.md
Daniel Stenberg e694c8284a
docs/libcurl/opts: clarify the return values
Expand a little.

- mention the type name of the return code
- avoid stating which exact return codes that might be returned, as that
  varies over time, builds and conditions
- avoid stating some always return OK
- refer to the manpage documenting all the return codes

Closes #15900
2025-01-02 17:13:33 +01:00

85 lines
1.8 KiB
Markdown

---
c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
SPDX-License-Identifier: curl
Title: CURLMOPT_PIPELINING
Section: 3
Source: libcurl
See-also:
- CURLMOPT_CHUNK_LENGTH_PENALTY_SIZE (3)
- CURLMOPT_CONTENT_LENGTH_PENALTY_SIZE (3)
- CURLMOPT_MAXCONNECTS (3)
- CURLMOPT_MAX_HOST_CONNECTIONS (3)
- CURLMOPT_MAX_PIPELINE_LENGTH (3)
- CURLMOPT_PIPELINING_SITE_BL (3)
Protocol:
- HTTP
Added-in: 7.16.0
---
# NAME
CURLMOPT_PIPELINING - enable HTTP multiplexing
# SYNOPSIS
~~~c
#include <curl/curl.h>
CURLMcode curl_multi_setopt(CURLM *handle, CURLMOPT_PIPELINING, long bitmask);
~~~
# DESCRIPTION
Pass in the correct value in the **bitmask** parameter to instruct libcurl to
enable multiplexing for this multi handle.
With multiplexing enabled, libcurl attempts to do multiple transfers over the
same connection when doing parallel transfers to the same hosts.
## CURLPIPE_NOTHING (0)
Make no attempts at multiplexing.
## CURLPIPE_HTTP1 (1)
This bit is deprecated and has no effect since version 7.62.0.
## CURLPIPE_MULTIPLEX (2)
If this bit is set, libcurl tries to multiplex the new transfer over an
existing connection if possible. This requires HTTP/2 or HTTP/3.
# DEFAULT
**CURLPIPE_MULTIPLEX**
# %PROTOCOLS%
# EXAMPLE
~~~c
int main(void)
{
CURLM *m = curl_multi_init();
/* try HTTP/2 multiplexing */
curl_multi_setopt(m, CURLMOPT_PIPELINING, CURLPIPE_MULTIPLEX);
}
~~~
# HISTORY
The multiplex support bit was added in 7.43.0. HTTP/1 Pipelining support was
disabled in 7.62.0.
Since 7.62.0, **CURLPIPE_MULTIPLEX** is enabled by default.
Before that, default was **CURLPIPE_NOTHING**.
# %AVAILABILITY%
# RETURN VALUE
curl_multi_setopt(3) returns a CURLMcode indicating success or error.
CURLM_OK (0) means everything was OK, non-zero means an error occurred, see
libcurl-errors(3).