CURLOPT_HSTSWRITEDATA - pointer passed to the HSTS write callback

Added in curl 7.74.0

NULL

Data pointer to pass to the HSTS write function. If you use the CURLOPT_HSTSWRITEFUNCTION(3) option, this is the pointer you get as input in the fourth argument to the callback. This option does not enable HSTS, you need to use CURLOPT_HSTS_CTRL(3) to do that.

struct MyData { void *custom; }; int main(void) { CURL *curl = curl_easy_init(); struct MyData this; if(curl) { curl_easy_setopt(curl, CURLOPT_URL, "http://example.com"); /* pass pointer that gets passed in to the CURLOPT_HSTSWRITEFUNCTION callback */ curl_easy_setopt(curl, CURLOPT_HSTSWRITEDATA, &this); curl_easy_perform(curl); } }

CURLOPT_HSTSWRITEDATA - pointer passed to the HSTS write callback

This functionality affects http only

This returns CURLE_OK.

CURLOPT_HSTS(3), CURLOPT_HSTSREADDATA(3), CURLOPT_HSTSREADFUNCTION(3), CURLOPT_HSTSWRITEFUNCTION(3) libcurl 2025-06-16 CURLOPT_HSTSWRITEDATA(3)

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