.\" **************************************************************************
.\" *                                  _   _ ____  _
.\" *  Project                     ___| | | |  _ \| |
.\" *                             / __| | | | |_) | |
.\" *                            | (__| |_| |  _ <| |___
.\" *                             \___|\___/|_| \_\_____|
.\" *
.\" * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
.\" *
.\" * This software is licensed as described in the file COPYING, which
.\" * you should have received as part of this distribution. The terms
.\" * are also available at https://curl.se/docs/copyright.html.
.\" *
.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
.\" * copies of the Software, and permit persons to whom the Software is
.\" * furnished to do so, under the terms of the COPYING file.
.\" *
.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
.\" * KIND, either express or implied.
.\" *
.\" * SPDX-License-Identifier: curl
.\" *
.\" **************************************************************************
.\"
.TH CURLINFO_CONN_ID 3 "07 June 2023" "libcurl" "libcurl"
.SH NAME
CURLINFO_CONN_ID \- get the ID of the last connection used by the handle
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_CONN_ID,
                           curl_off_t *conn_id);
.fi
.SH DESCRIPTION
Pass a pointer to a \fIcurl_off_t\fP 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.

.SH PROTOCOLS
All
.SH EXAMPLE
.nf
CURL *curl = curl_easy_init();
if(curl) {
  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);
    }
  }
}
.fi
.SH AVAILABILITY
Added in 8.2.0
.SH RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
.SH "SEE ALSO"
.BR curl_easy_getinfo "(3), " curl_easy_setopt "(3), "
.BR CURLINFO_XFER_ID "(3), "