CURLOPT_STREAM_WEIGHT(3)

🎀 NAME 🎀

okay bestie, welcome to the libcurl page for CURLOPT_STREAM_WEIGHT(3), from the Library Functions Manual — and it is literally all about numerical stream weight 💅

• CURLOPT_STREAM_WEIGHT — numerical stream weight, periodt.

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✨ SYNOPSIS ✨

include the header, then call it like this:

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_STREAM_WEIGHT, long weight);

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💖 DESCRIPTION 💖

Set the long weight to a number between 1 and 256.

When you're using HTTP/2, this option sets the individual weight for this particular stream used by the easy handle. 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 CURLMOPT_PIPELINING(3).

This option can be set during transfer and causes 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 👑

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 gets two thirds (32/48) of the available bandwidth (assuming the server can send off the data equally for both streams). math is mathing, no cap 🧮✨

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🌸 DEFAULT 🌸

16 — that's the default, bestie.

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🦋 PROTOCOLS 🦋

This functionality affects http only.

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🍓 EXAMPLE 🍓

here's the whole example, pls enjoy:

int main(void)
{
  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 */
  }
}

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⭐ AVAILABILITY ⭐

Added in curl 7.46.0.

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💜 RETURN VALUE 💜

curl_easy_setopt(3) returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors(3).

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🌈 SEE ALSO 🌈

go peek at these besties:

• CURLMOPT_PIPELINING(3)
• CURLOPT_PIPEWAIT(3)
• CURLOPT_STREAM_DEPENDS(3)
• CURLOPT_STREAM_DEPENDS_E(3)

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signing off from the libcurl manual, dated 2026-10-12, on the CURLOPT_STREAM_WEIGHT(3) page — mwah 💋