CURLINFO_XFER_ID - get the ID of a transfer

Added in curl 8.2.0

Pass a pointer to a curl_off_t to receive the identifier of the current/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.

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); } } } }

CURLINFO_XFER_ID - get the ID of a transfer

This functionality affects all supported protocols

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).

CURLINFO_CONN_ID(3), curl_easy_getinfo(3), curl_easy_setopt(3) libcurl 2025-06-16 CURLINFO_XFER_ID(3)

#include <curl/curl.h> CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_XFER_ID, curl_off_t *xfer_id);