82 lines
2 KiB
Markdown
82 lines
2 KiB
Markdown
---
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c: Copyright (C) Daniel Stenberg, <daniel.se>, et al.
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SPDX-License-Identifier: curl
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Title: CURLOPT_STREAM_WEIGHT
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Section: 3
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Source: libcurl
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See-also:
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- CURLMOPT_PIPELINING (3)
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- CURLOPT_PIPEWAIT (3)
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- CURLOPT_STREAM_DEPENDS (3)
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- CURLOPT_STREAM_DEPENDS_E (3)
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---
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# NAME
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CURLOPT_STREAM_WEIGHT - numerical stream weight
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# SYNOPSIS
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~~~c
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#include <curl/curl.h>
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CURLcode curl_easy_setopt(CURL *handle, CURLOPT_STREAM_WEIGHT, long weight);
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~~~
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# DESCRIPTION
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Set the long *weight* to a number between 1 and 256.
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When using HTTP/2, this option sets the individual weight for this particular
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stream used by the easy *handle*. Setting and using weights only makes
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sense and is only usable when doing multiple streams over the same
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connections, which thus implies that you use CURLMOPT_PIPELINING(3).
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This option can be set during transfer and causes the updated weight info get
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sent to the server the next time an HTTP/2 frame is sent to the server.
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See section 5.3 of RFC 7540 for protocol details.
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Streams with the same parent should be allocated resources proportionally
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based on their weight. If you have two streams going, stream A with weight 16
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and stream B with weight 32, stream B gets two thirds (32/48) of the available
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bandwidth (assuming the server can send off the data equally for both
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streams).
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# DEFAULT
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If nothing is set, the HTTP/2 protocol itself uses its own default which is
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16.
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# PROTOCOLS
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HTTP/2
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# EXAMPLE
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~~~c
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int main(void)
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{
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CURL *curl = curl_easy_init();
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CURL *curl2 = curl_easy_init(); /* a second handle */
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if(curl) {
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curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/one");
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curl_easy_setopt(curl, CURLOPT_STREAM_WEIGHT, 10L);
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/* the second has twice the weight */
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curl_easy_setopt(curl2, CURLOPT_URL, "https://example.com/two");
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curl_easy_setopt(curl2, CURLOPT_STREAM_WEIGHT, 20L);
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/* then add both to a multi handle and transfer them! */
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}
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}
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~~~
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# AVAILABILITY
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Added in 7.46.0
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# RETURN VALUE
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Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
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