CURLSHOPT_UNLOCKFUNC(3)

💅 CURLSHOPT_UNLOCKFUNC 💅

okay so bestie, welcome to the Library Functions Manual page for CURLSHOPT_UNLOCKFUNC — it's the mutex unlock callback situation in libcurl, and yes it matters 🫶✨

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🌸 NAME 🌸

CURLSHOPT_UNLOCKFUNC — mutex unlock callback ✨

✨ SYNOPSIS ✨

#include <curl/curl.h>

void unlockcb(CURL *handle, curl_lock_data data, void *clientp);

CURLSHcode curl_share_setopt(CURLSH *share, CURLSHOPT_UNLOCKFUNC, unlockcb);

🦋 DESCRIPTION 🦋

Set a mutex unlock callback for the share object. There's a corresponding CURLSHOPT_LOCKFUNC(3) callback that gets called when the mutex is first locked — iconic pairing 💅.

The unlockcb argument has to be a pointer to a function matching the prototype shown above. The arguments your callback receives are:

• handle — the currently active easy handle in use when the share object is released 👑.
• data — tells you what kind of data libcurl wants to unlock. Make sure that the callback uses a different lock for each kind of data, fr fr 🫶.
• clientp — the private pointer you set with CURLSHOPT_USERDATA(3). This pointer is not used by libcurl itself 🙈.

🌈 PROTOCOLS 🌈

This functionality affects all supported protocols. all of them, periodt 🌈✨

🍓 EXAMPLE 🍓

extern void mutex_unlock(CURL *, curl_lock_data, void *);

int main(void)
{
  CURLSHcode sh;
  CURLSH *share = curl_share_init();
  sh = curl_share_setopt(share, CURLSHOPT_UNLOCKFUNC, mutex_unlock);
  if(sh)
    printf("Error: %s\n", curl_share_strerror(sh));
}

⭐ AVAILABILITY ⭐

Added in curl 7.10.3 — vintage but iconic 💖.

💖 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 — that's your error-decoder bestie.

🎀 SEE ALSO 🎀

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

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mwah 💋 this page is from libcurl, dated 2026-10-12, and it's the CURLSHOPT_UNLOCKFUNC(3) manual-page moment. bye bestie 🫶🎀