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 is passed in to
       the respective callback.

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

       If  you  are  using  libcurl  as  a  win32 DLL, you MUST use a CURLOPT_WRITEFUNCTION(3) or
       CURLOPT_HEADERFUNCTION(3) if you set this option or you might experience crashes.

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 = userdata;
         printf("shoe size: %d\n", i->shoesize);
         /* now this callback can access the my_info struct */

         return nitems * size;
       }

       int main(void)
       {
         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);
         }
       }

AVAILABILITY

       Always

RETURN VALUE

       Returns CURLE_OK

SEE ALSO

       curl_easy_header(3), CURLOPT_HEADERFUNCTION(3), CURLOPT_WRITEFUNCTION(3)