curl/docs/libcurl/opts/CURLINFO_CONN_ID.3

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.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), "