curl/docs/libcurl/opts/CURLOPT_PRIVATE.md
Daniel Stenberg 54ded66618
docs/libcurl: improve easy setopt examples
- always assign the curl_easy_perform() return code (and declare
  the necessary 'result' variable for it)

- always call curl_easy_cleanup() on the created easy handles

Closes #21364
2026-04-18 23:34:39 +02:00

1.5 KiB

c SPDX-License-Identifier Title Section Source See-also Protocol Added-in
Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. curl CURLOPT_PRIVATE 3 libcurl
CURLINFO_PRIVATE (3)
CURLOPT_STDERR (3)
CURLOPT_VERBOSE (3)
All
7.10.3

NAME

CURLOPT_PRIVATE - store a private pointer

SYNOPSIS

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PRIVATE, void *pointer);

DESCRIPTION

Pass a void * as parameter, pointing to data that should be associated with this curl handle. The pointer can subsequently be retrieved using curl_easy_getinfo(3) with the CURLINFO_PRIVATE(3) option. libcurl itself never does anything with this data.

DEFAULT

NULL

%PROTOCOLS%

EXAMPLE

struct private {
  void *custom;
};

int main(void)
{
  CURL *curl = curl_easy_init();
  struct private secrets;
  if(curl) {
    CURLcode result;
    struct private *extracted;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

    /* store a pointer to our private struct */
    curl_easy_setopt(curl, CURLOPT_PRIVATE, &secrets);

    result = curl_easy_perform(curl);

    /* we can extract the private pointer again too */
    curl_easy_getinfo(curl, CURLINFO_PRIVATE, &extracted);

    curl_easy_cleanup(curl);
  }
}

%AVAILABILITY%

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).