CURLINFO_XFER_ID(3) Library Functions Manual CURLINFO_XFER_ID(3)
NAME
CURLINFO_XFER_ID - get the ID of a transfer
SYNOPSIS
#include <curl/curl.h>
CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_XFER_ID,
curl_off_t *xfer_id);
DESCRIPTION
Pass a pointer to a curl_off_t to receive the identifier of the cur-
rent/last transfer done with the handle. Stores -1 if no transfer has
been started yet for the handle.
The transfer id is unique among all transfers performed using the same
connection cache. This is implicitly the case for all transfers 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 xfer_id;
res = curl_easy_getinfo(curl, CURLINFO_XFER_ID, &xfer_id);
if(!res) {
printf("Transfer ID: %" CURL_FORMAT_CURL_OFF_T "\n", xfer_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_CONN_ID(3), curl_easy_getinfo(3), curl_easy_setopt(3)
libcurl 2026-07-12 CURLINFO_XFER_ID(3)
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