curl/docs/libcurl/opts/CURLINFO_CONN_ID.md

---

c: Copyright (C) Daniel Stenberg, daniel@haxx.se, et al. SPDX-License-Identifier: curl Title: CURLINFO_CONN_ID Section: 3 Source: libcurl See-also:

• CURLINFO_XFER_ID (3)
• curl_easy_getinfo (3)
• curl_easy_setopt (3) Protocol:
• All Added-in: 8.2.0 ---

NAME

CURLINFO_CONN_ID - get the ID of the last connection used by the handle

SYNOPSIS

#include <curl/curl.h>

CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_CONN_ID,
                           curl_off_t *conn_id);

DESCRIPTION

Pass a pointer to a curl_off_t to receive the connection identifier last used by the handle. Stores -1 if there was no connection used.

The connection id is unique among all connections using the same connection cache. This is implicitly the case for all connections in the same multi handle.

%PROTOCOLS%

EXAMPLE

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;

    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

    /* Perform the request */
    res = curl_easy_perform(curl);

    if(!res) {
      curl_off_t conn_id;
      res = curl_easy_getinfo(curl, CURLINFO_CONN_ID, &conn_id);
      if(!res) {
        printf("Connection used: %" CURL_FORMAT_CURL_OFF_T "\n", conn_id);
      }
    }
  }
}

%AVAILABILITY%

RETURN VALUE

Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.