CURLOPT_PROGRESSDATA − custom pointer passed to the progress callback
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROGRESSDATA, void *pointer);
Pass a pointer that will be untouched by libcurl and passed as the first argument in the progress callback set with CURLOPT_PROGRESSFUNCTION(3).
The default value of this parameter is NULL.
All
http://curl.haxx.se/libcurl/c/progressfunc.html
Always
Returns CURLE_OK