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CURLOPT_HEADERDATA

Section: curl_easy_setopt options (3)
Updated: May 05, 2017
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NAME

CURLOPT_HEADERDATA - pointer to pass to header callback

SYNOPSIS

#include <curl/curl.h>

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

DESCRIPTION

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.

DEFAULT

NULL

PROTOCOLS

All

EXAMPLE

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, "http://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);
}

AVAILABILITY

Always

RETURN VALUE

Returns CURLE_OK