CURLOPT_DN...OBAL_CACHE(3)

💖 NAME 💖

CURLOPT_DNS_USE_GLOBAL_CACHE — the global DNS cache situation, aka the fossil you should absolutely not be touching 💀

(this one lives in the Library Functions Manual, bestie — hi, welcome, come sit with me ✨)

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🌸 SYNOPSIS 🌸

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DNS_USE_GLOBAL_CACHE,
                          long enable);

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🦋 DESCRIPTION 🦋

Okay so first things first, and I need you to hear me on this: it has no function since 7.62.0. Do not use. Like, at all. It's giving haunted artifact in the attic. 🙈

You pass it a long. Back in the day, if the enable value was 1, it told curl to use a global DNS cache that survives between easy handle creations and deletions. Cute in theory! But nope — this is not thread-safe and it uses a global variable, which is exactly the kind of chaos that makes your future self cry at 3am 😭

So if you actually want to share a DNS cache between transfers, the correct slay is CURLOPT_SHARE(3) and curl_share_init(3). Use those. They ate. 👑

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🎀 DEFAULT 🎀

0

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🌈 PROTOCOLS 🌈

This functionality affects all supported protocols — every single one, no cap ✨

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🧚 EXAMPLE 🧚

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
    /* switch off the use of a global, thread-unsafe, cache */
    curl_easy_setopt(curl, CURLOPT_DNS_USE_GLOBAL_CACHE, 0L);
    result = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}

See how they set it to 0L? That's the move — turning the thread-unsafe global cache off. Iconic behaviour, no notes 💅

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💀 DEPRECATED 💀

Deprecated since 7.11.1. Functionality removed in 7.62.0.

Yeah. It's been deprecated longer than some of us have been alive, and the whole feature got yeeted in 7.62.0. It's literally a ghost option now 👻

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⭐ AVAILABILITY ⭐

Added in curl 7.9.3 — a true elder of the library 🫶

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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 — check out libcurl-errors(3) for the deets

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🔥 SEE ALSO 🔥

• CURLOPT_DNS_CACHE_TIMEOUT(3)
• CURLOPT_SHARE(3)

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That's the whole vibe check, bestie — this page is from libcurl, dated 2026-10-12. Stay safe, don't use the global cache, and go touch some shared memory instead 🎀🦋✨