curl/docs/libcurl/opts/CURLOPT_HSTSREADDATA.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

1.6 KiB

c SPDX-License-Identifier Title Section Source Protocol See-also Added-in
Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. curl CURLOPT_HSTSREADDATA 3 libcurl
HTTP
CURLOPT_HSTS (3)
CURLOPT_HSTSREADFUNCTION (3)
CURLOPT_HSTSWRITEDATA (3)
CURLOPT_HSTSWRITEFUNCTION (3)
7.74.0

NAME

CURLOPT_HSTSREADDATA - pointer passed to the HSTS read callback

SYNOPSIS

#include <curl/curl.h>

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

DESCRIPTION

Data pointer to pass to the HSTS read function. If you use the CURLOPT_HSTSREADFUNCTION(3) option, this is the pointer you get as input in the 3rd argument to the callback.

This option does not enable HSTS, you need to use CURLOPT_HSTS_CTRL(3) to do that.

DEFAULT

NULL

%PROTOCOLS%

EXAMPLE

struct MyData {
  void *custom;
};

static CURLSTScode hsts_cb(CURL *easy, struct curl_hstsentry *sts,
                           void *clientp)
{
  /* populate the struct as documented */
  return CURLSTS_OK;
}

int main(void)
{
  CURL *curl = curl_easy_init();
  struct MyData this;
  if(curl) {
    CURLcode result;
    curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");

    /* pass pointer that gets passed in to the
       CURLOPT_HSTSREADFUNCTION callback */
    curl_easy_setopt(curl, CURLOPT_HSTSREADDATA, &this);
    /* set HSTS read callback */
    curl_easy_setopt(curl, CURLOPT_HSTSREADFUNCTION, hsts_cb);

    result = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}

%AVAILABILITY%

RETURN VALUE

This returns CURLE_OK.