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3rdparty/curl/share/man/man3/CURLOPT_STREAM_WEIGHT.3 3.08 KB
a86c63ca   Hu Chunming   提交三方库文件
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  .\" **************************************************************************
  .\" *                                  _   _ ____  _
  .\" *  Project                     ___| | | |  _ \| |
  .\" *                             / __| | | | |_) | |
  .\" *                            | (__| |_| |  _ <| |___
  .\" *                             \___|\___/|_| \_\_____|
  .\" *
  .\" * Copyright (C) 1998 - 2020, 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.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 CURLOPT_STREAM_WEIGHT 3 "November 04, 2020" "libcurl 7.77.0" "curl_easy_setopt options"
  
  .SH NAME
  CURLOPT_STREAM_WEIGHT \- set numerical stream weight
  .SH SYNOPSIS
  #include <curl/curl.h>
  
  CURLcode curl_easy_setopt(CURL *handle, CURLOPT_STREAM_WEIGHT, long weight);
  .SH DESCRIPTION
  Set the long \fIweight\fP to a number between 1 and 256.
  
  When using HTTP/2, this option sets the individual weight for this particular
  stream used by the easy \fIhandle\fP. Setting and using weights only makes
  sense and is only usable when doing multiple streams over the same
  connections, which thus implies that you use \fICURLMOPT_PIPELINING(3)\fP.
  
  This option can be set during transfer and will then cause the updated weight
  info get sent to the server the next time an HTTP/2 frame is sent to the
  server.
  
  See section 5.3 of RFC 7540 for protocol details:
  https://httpwg.github.io/specs/rfc7540.html#StreamPriority
  
  Streams with the same parent should be allocated resources proportionally
  based on their weight. So if you have two streams going, stream A with weight
  16 and stream B with weight 32, stream B will get two thirds (32/48) of the
  available bandwidth (assuming the server can send off the data equally for
  both streams).
  .SH DEFAULT
  If nothing is set, the HTTP/2 protocol itself will use its own default which
  is 16.
  .SH PROTOCOLS
  HTTP/2
  .SH EXAMPLE
  .nf
  CURL *curl = curl_easy_init();
  CURL *curl2 = curl_easy_init(); /* a second handle */
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/one");
    curl_easy_setopt(curl, CURLOPT_STREAM_WEIGHT, 10L);
  
    /* the second has twice the weight */
    curl_easy_setopt(curl2, CURLOPT_URL, "https://example.com/two");
    curl_easy_setopt(curl2, CURLOPT_STREAM_WEIGHT, 20L);
  
    /* then add both to a multi handle and transfer them! */
  }
  .fi
  .SH AVAILABILITY
  Added in 7.46.0
  .SH RETURN VALUE
  Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
  .SH "SEE ALSO"
  .BR CURLOPT_STREAM_DEPENDS "(3), " CURLOPT_STREAM_DEPENDS_E "(3), "
  .BR CURLOPT_PIPEWAIT "(3), " CURLMOPT_PIPELINING "(3), "