CURLSHOPT_USERDATA(3)

💅 CURLSHOPT_USERDATA(3) 💅

okay so bestie, welcome to the libcurl Library Functions Manual page for CURLSHOPT_USERDATA — and yes this is exactly as niche and iconic as it sounds 🎀

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✨ NAME ✨

CURLSHOPT_USERDATA — the pointer that gets passed to the lock and unlock mutex callbacks 🫶

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🌸 SYNOPSIS 🌸

#include <curl/curl.h>

CURLSHcode curl_share_setopt(CURLSH *share, CURLSHOPT_USERDATA, void *clientp);

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🦋 DESCRIPTION 🦋

So here's the tea, bestie: libcurl holds onto that clientp parameter verbatim — like, it does not copy it, does not peek inside, does not judge it, nothing. It just holds it. 💀

And then it passes that same thing on as the clientp argument to the callbacks you set up with CURLSHOPT_LOCKFUNC(3) and CURLSHOPT_UNLOCKFUNC(3). That's it. That's the whole job. Hand it a pointer, it hands it back to your callbacks. Simple, clean, slay. ✨

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🌈 PROTOCOLS 🌈

This functionality affects all supported protocols 👑 (all of them, no cap)

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🍓 EXAMPLE 🍓

struct secrets {
  void *custom;
};

int main(void)
{
  CURLSHcode sh;
  struct secrets private_stuff;
  CURLSH *share = curl_share_init();
  sh = curl_share_setopt(share, CURLSHOPT_USERDATA, &private_stuff);
  if(sh)
    printf("Error: %s\n", curl_share_strerror(sh));
}

look at her go 😭 she's passing &private_stuff in and letting libcurl hold it. main character pointer energy fr fr.

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⭐ AVAILABILITY ⭐

Added in curl 7.10.3 — retro icon behavior, honestly 💜

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💖 RETURN VALUE 💖

CURLSHE_OK (zero) means that the option was set properly 🎉 — non-zero means an error occurred 🙈. See libcurl-errors(3) for the full list with descriptions, iykyk.

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🧚 SEE ALSO 🧚

• CURLSHOPT_LOCKFUNC(3)
• curl_share_cleanup(3)
• curl_share_init(3)
• curl_share_setopt(3)

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💅 reminder bestie: libcurl holds your clientp verbatim — it does not copy it. So keep that memory alive for as long as your callbacks might need it. No dangling pointers on my watch 🫶

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mwah, that's a wrap 🎀 brought to you by libcurl, dated 2026-10-12, from the CURLSHOPT_USERDATA(3) page — go forth and share responsibly, queen 👑✨