CURLMOPT_MAX_CONCURRENT_STREAMS(3)

💅 CURLMOPT_MAX_CONCURRENT_STREAMS(3) 💅

okay bestie, welcome to the Library Functions Manual section, where we talk about CURLMOPT_MAX_CONCURRENT_STREAMS — say that five times fast, I dare you 😭 this one is literally the "how many streams tho" knob for your multi handle. let's get into it ✨

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🌸 NAME 🌸

CURLMOPT_MAX_CONCURRENT_STREAMS — the max concurrent streams for http2, no cap 🫶

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✨ SYNOPSIS ✨

#include <curl/curl.h>

CURLMcode curl_multi_setopt(CURLM *handle, CURLMOPT_MAX_CONCURRENT_STREAMS,
                            long max);

so you're gonna pull in the header, then hit curl_multi_setopt with your multi handle, the option name, and a long max. that's the whole vibe 💖

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🦋 DESCRIPTION 🦋

okay so here's the tea ☕ — you pass a long that indicates the max. that number you set? it becomes the maximum number of concurrent streams libcurl should support on connections done using HTTP/2 or HTTP/3. it's giving "how many lanes on the highway" energy 🔥

valid values range from 1 to 2147483647 (2^31 - 1), and it defaults to 100. periodt 💅

but real talk — the value you pass here would be honored based on other system resources properties. so like, it's a request, not a guarantee, and the system gets a say too 🙈 keep that in mind bestie, it's important.

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🎀 DEFAULT 🎀

100

that's the starting point, the factory setting, the main character default 👑

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🌈 PROTOCOLS 🌈

this functionality affects http only. just http. that's it. that's the whole list 💀

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💜 EXAMPLE 💜

here's what it looks like in the wild, copy-paste ready:

int main(void)
{
  CURLM *m = curl_multi_init();
  /* max concurrent streams 200 */
  curl_multi_setopt(m, CURLMOPT_MAX_CONCURRENT_STREAMS, 200L);
}

see that 200L? we said 200 streams. icon behavior honestly 🍓

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⭐ AVAILABILITY ⭐

Added in curl 7.67.0 — so if you're on something ancient, this one's not gonna be there for you, sorry bestie 😭

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🧚 RETURN VALUE 🧚

curl_multi_setopt(3) returns a CURLMcode indicating success or error. so like, always check it, okay? 🫶

• CURLM_OK (0) means everything was OK 💖
• non-zero means an error occurred — go see libcurl-errors(3) for the whole breakdown 🔍

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👑 SEE ALSO 👑

• CURLMOPT_MAXCONNECTS(3)
• CURLOPT_MAXCONNECTS(3)

go read those too, they're the sibling energy this page deserves 🌸

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heads up bestie: that upper bound is literally 2147483647 (2^31 - 1), so don't go passing something wilder than that and expecting slay behavior 💀

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and that's the whole page! brought to you by libcurl, dated 2026-10-12 — mwah, go forth and stream responsibly 💅✨🎀