CURLINFO_LOCAL_PORT(3)

📦
version 8.18.0 · 24 versions
, in fedora 44

💅 CURLINFO_LOCAL_PORT(3) 💅

okay so bestie, we're in the libcurl section of the manual — Library Functions Manual, if you wanna be formal about it — and today's main character is CURLINFO_LOCAL_PORT: the latest local port number. no cap, that's the whole vibe. 🎀

✨ NAME ✨

CURLINFO_LOCAL_PORT — latest local port number 🦋

✨ SYNOPSIS ✨

#include <curl/curl.h>

CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_LOCAL_PORT, long *portp);

🌸 DESCRIPTION 🌸

so what you do is, you pass a pointer to a long, and it receives the local port number of the most recent connection done with this curl handle. literally that's it. 🫶

if the connection was done using QUIC, the port number is a UDP port number, otherwise it is a TCP port number. iykyk. 🔥

and if no connection was established, or if the protocol doesn't use ports — no shade to it — then -1 is returned. periodt. 💀

🧚 PROTOCOLS 🧚

this functionality affects quic and tcp. that's the vibe check, and they both passed. ✅

🌈 EXAMPLE 🌈

here's the whole thing, copy it exactly, don't @ me:

int main(void)
{
  CURL *curl;
  CURLcode result;

  curl = curl_easy_init();
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
    result = curl_easy_perform(curl);

    if(CURLE_OK == result) {
      long port;
      result = curl_easy_getinfo(curl, CURLINFO_LOCAL_PORT, &port);

      if(CURLE_OK == result) {
        printf("We used local port: %ld\n", port);
      }
    }
    curl_easy_cleanup(curl);
  }
  return 0;
}

like, iconic. it just prints We used local port: %ld and honestly? ate. 👑

⭐ AVAILABILITY ⭐

added in curl 7.21.0 — so she's been serving since way back. vintage queen. 🎀

💖 RETURN VALUE 💖

curl_easy_getinfo(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) for the full rundown.

🌟 SEE ALSO 🌟

go read them, bestie, they're all linked in the group chat. 💜

okay that's the whole page — this one's from libcurl, dated 2026-10-12, and it was CURLINFO_LOCAL_PORT(3) the whole time. mwah. 💅✨🦋

📦 where this page comes from