CURLINFO_CONN_ID(3) Library Functions Manual CURLINFO_CONN_ID(3)
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 connec-
tion cache. This is implicitly the case for all connections in the same
multi handle.
PROTOCOLS
This functionality affects all supported 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
Added in curl 8.2.0
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).
SEE ALSO
CURLINFO_XFER_ID(3), curl_easy_getinfo(3), curl_easy_setopt(3)
libcurl 2026-07-12 CURLINFO_CONN_ID(3)
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