CURLOPT_XFERINFODATA(3)

CURLOPT_XFERINFODATA3

Pointer passed to the progress callback

Usage

#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_XFERINFODATA, void *pointer);

Overview

Pass a pointer that is untouched by libcurl and passed as the first argument in the progress callback set with CURLOPT_XFERINFOFUNCTION(3).

This is an alias for CURLOPT_PROGRESSDATA(3).

Default

NULL

Protocols

This functionality affects all supported protocols

Examples

struct progress {
  char *private_data;
  size_t size;
};
static int progress_cb(void *clientp,
                       curl_off_t dltotal,
                       curl_off_t dlnow,
                       curl_off_t ultotal,
                       curl_off_t ulnow)
{
  struct progress *memory = clientp;
  printf("private ptr: %p\n", (void *)memory->private_data);
  /* use the values */
  return 0; /* all is good */
}
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    struct progress data;
    /* pass struct to callback */
    curl_easy_setopt(curl, CURLOPT_XFERINFODATA, &data);
    curl_easy_setopt(curl, CURLOPT_XFERINFOFUNCTION, progress_cb);
  }
}

Return value

curl_easy_setopt(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).

Releases

7 releases since Debian 8 (Jessie); the text changed 6 times.

  1. 8
  2. 9
  3. 10
  4. 11
  5. 12
  6. 13
  7. Arch

Availability

Added in curl 7.32.0

From curl 8.23.0-1 in Arch Linux 2026-11-01. Parsed by carta from the page's man source.