This function will return a new curl handle, a duplicate, using all the
options previously set in the input curl handle. Both handles can
subsequently be used independently and they must both be freed with
All strings that the input handle has been told to point to (as opposed to
copy) with previous calls to curl_easy_setopt(3) using char * inputs,
will be pointed to by the new handle as well. You must therefore make sure to
keep the data around until both handles have been cleaned up.
The new handle will not inherit any state information, no connections,
no SSL sessions and no cookies.
Note that even in multi-threaded programs, this function must be called
in a synchronous way, the input handle may not be in use when cloned.
If this function returns NULL, something went wrong and no valid handle was