curl_multi_setopt() is used to tell a libcurl multi handle how to behave. By
using the appropriate options to curl_multi_setopt, you can change
libcurl's behaviour when using that multi handle. All options are set with
the option followed by the parameter param. That parameter can be
a long, a function pointer, an object pointer or a
curl_off_t type, depending on what the specific option expects. Read
this manual carefully as bad input values may cause libcurl to behave badly!
You can only set one option in each function call.
OPTIONS
CURLMOPT_SOCKETFUNCTION
Pass a pointer to a function matching the curl_socket_callback prototype. The
curl_multi_socket(3) functions inform the application about updates in
the socket (file descriptor) status by doing none, one or multiple calls to
the curl_socket_callback given in the param argument. They update the
status with changes since the previous time a curl_multi_socket(3)
function was called. If the given callback pointer is NULL, no callback will
be called. Set the callback's userp argument with
CURLMOPT_SOCKETDATA. See curl_multi_socket(3) for more callback
details.
CURLMOPT_SOCKETDATA
Pass a pointer to whatever you want passed to the curl_socket_callback's forth
argument, the userp pointer. This is not used by libcurl but only passed-thru
as-is. Set the callback pointer with CURLMOPT_SOCKETFUNCTION.
RETURNS
The standard CURLMcode for multi interface error codes. Note that it returns a
CURLM_UNKNOWN_OPTION if you try setting an option that this version of libcurl
doesn't know of.
