Unknown option: "-3" Unix manual page for curl_easy_duphandle. (host=minya system=Darwin)
curl_easy_duphandle(3)          libcurl Manual          curl_easy_duphandle(3)

NAME
       curl_easy_duphandle - Clone a libcurl session handle

SYNOPSIS
       #include <curl/curl.h>

       CURL *curl_easy_duphandle(CURL *handle);

DESCRIPTION
       This function will return a new curl handle, a duplicate, using all the
       options previously set in the input curl handle. Both handles can  sub-
       sequently  be  used  independently  and  they  must  both be freed with
       curl_easy_cleanup(3).

       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  there-
       fore  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.

RETURN VALUE
       If this function returns NULL, something went wrong and no valid handle
       was returned.

SEE ALSO
       curl_easy_init(3),curl_easy_cleanup(3),curl_easy_reset(3),
       curl_global_init(3)

libcurl 7.54.0                 February 03, 2016        curl_easy_duphandle(3)