Manpages - CURLOPT_HEADERDATA.3

CURLOPT_HEADERDATA - pointer to pass to header callback

#include <curl/curl.h>

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

Pass a pointer to be used to write the header part of the received data to.

If CURLOPT_WRITEFUNCTION(3) or CURLOPT_HEADERFUNCTION(3) is used, pointer will be passed in to the respective callback.

If neither of those options are set, pointer must be a valid FILE * and it will be used by a plain fwrite() to write headers to.

NULL

All

  struct my_info {
    int shoesize;
    char *secret;
  };

  static size_t header_callback(char *buffer, size_t size,
                                size_t nitems, void *userdata)
  {
    struct my_info *i = (struct my_info *)userdata;

    /* now this callback can access the my_info struct */

    return nitems * size;
  }

  CURL *curl = curl_easy_init();
  if(curl) {
    struct my_info my = { 10, "the cookies are in the cupboard" };
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

    curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, header_callback);

    /* pass in custom data to the callback */
    curl_easy_setopt(curl, CURLOPT_HEADERDATA, &my);

    curl_easy_perform(curl);
  }

Always

Returns CURLE_OK

*CURLOPT_HEADERFUNCTION*(3), *CURLOPT_WRITEFUNCTION*(3),