# curl_share_setopt

Definition: | include builtins\libcurl.e CURLSHcode res = curl_share_setopt(atom share, CURLSHoption option, atom param)
Description: | Set options for a shared object. Set the option to parameter for the given share. Return value CURLSHE_OK (zero) means that the option was set properly, non-zero means an error occurred (see CURLSHcode).
pwa/p2js: | Not supported.
CURLSHoption | CURLSHoption is one of the following:
CURLSHOPT_LOCKFUNC | The param must be a call_back function matching the following prototype: Copy
    function lock_function(atom handle, curl_share_data data, curl_lock_access access, atom userptr)
        return 0 -- (the return value is ignored)
    end function
data defines what data libcurl wants to lock (see curl_share_data), and you must make sure that only one lock is given at any time for each kind of data. access defines what access type libcurl wants, shared or single (see curl_lock_access). userptr is the pointer you set with CURLSHOPT_USERDATA.
CURLSHOPT_UNLOCKFUNC | The param must be a call_back function matching the following prototype: Copy
    function unlock_function(atom handle, curl_share_data data, atom userptr)
        return 0 -- (the return value is ignored)
    end function
data defines what data libcurl wants to unlock (see curl_share_data), and you must make sure that only one lock is given at any time for each kind of data. userptr is the pointer you set with CURLSHOPT_USERDATA.
CURLSHOPT_SHARE | The parameter specifies a type of data that should be shared. See curl_share_data.
CURLSHOPT_UNSHARE | This option does the opposite of CURLSHOPT_SHARE. It specifies that the specified parameter will no longer be shared. Valid values are the same as those for CURLSHOPT_SHARE (see curl_share_data).
CURLSHOPT_USERDATA | The parameter allows you to specify a pointer to data that will be passed to the lock_function and unlock_function each time it is called.
curl_share_data | curl_share_data is one of the following:
CURL_LOCK_DATA_COOKIE | Cookie data will be shared across the easy handles using this shared object.
CURL_LOCK_DATA_DNS | Cached DNS hosts will be shared across the easy handles using this shared object. Note that when you use the multi interface, all easy handles added to the same multi handle will share DNS cache by default without this having to be used!
CURL_LOCK_DATA_SSL_SESSION | SSL session IDs will be shared across the easy handles using this shared object. This will reduce the time spent in the SSL handshake when reconnecting to the same server. Note SSL session IDs are reused within the same easy handle by default. Note this symbol was added in 7.10.3 but was not implemented until 7.23.0.
CURL_LOCK_DATA_CONNECT | Put the connection cache in the share object and make all easy handles using this share object share the connection cache. Using this, you can for example do multi-threaded libcurl use with one handle in each thread, and yet have a shared pool of unused connections and this way get way better connection re-use than if you use one separate pool in each thread. Connections that are used for HTTP/1.1 Pipelining or HTTP/2 multiplexing only get additional transfers added to them if the existing connection is held by the same multi or easy handle. libcurl does not support doing HTTP/2 streams in different threads using a shared connection. Support for CURL_LOCK_DATA_CONNECT was added in 7.57.0, but the symbol existed before this.
curl_lock_access | curl_lock_access is one of the following:
CURL_LOCK_ACCESS_SHARED | for read perhaps
CURL_LOCK_ACCESS_SINGLE | for write perhaps
See Also: | curl_share_cleanup, curl_share_init