curl/docs/libcurl/opts/CURLINFO_XFER_ID.3

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.TH CURLINFO_XFER_ID 3 "07 June 2023" "libcurl" "libcurl"
.SH NAME
CURLINFO_XFER_ID \- get the ID of a transfer
.SH SYNOPSIS
.nf
#include <curl/curl.h>

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

.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 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);
    }
  }
}
.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_CONN_ID "(3), "