focal (3) curl_share_setopt.3.gz
NAME
curl_share_setopt - Set options for a shared object
SYNOPSIS
#include <curl/curl.h>
CURLSHcode curl_share_setopt(CURLSH *share, CURLSHoption option, parameter);
DESCRIPTION
Set the option to parameter for the given share.
OPTIONS
CURLSHOPT_LOCKFUNC
The parameter must be a pointer to a function matching the following prototype:
void lock_function(CURL *handle, curl_lock_data data, curl_lock_access access, void *userptr);
The data argument tells what kind of data libcurl wants to lock. Make sure that the callback uses
a different lock for each kind of data.
access defines what access type libcurl wants, shared or single.
userptr is the pointer you set with CURLSHOPT_USERDATA.
CURLSHOPT_UNLOCKFUNC
The parameter must be a pointer to a function matching the following prototype:
void unlock_function(CURL *handle, curl_lock_data data, void *userptr);
data defines what data libcurl wants to unlock, 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. This may be set to one of the values
described below.
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 using this option.
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.
Note that when you use the multi interface, all easy handles added to the same multi handle
will share connection cache by default without using this option.
CURL_LOCK_DATA_PSL
The Public Suffix List stored in the share object is made available to all easy handle
bound to the later. Since the Public Suffix List is periodically refreshed, this avoids
updates in too many different contexts.
CURL_LOCK_DATA_PSL exists since 7.61.0.
Note that when you use the multi interface, all easy handles added to the same multi handle
will share PSL cache by default without using this option.
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.
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.
RETURN VALUE
CURLSHE_OK (zero) means that the option was set properly, non-zero means an error occurred as
<curl/curl.h> defines. See the libcurl-errors.3 man page for the full list with descriptions.
SEE ALSO
curl_share_cleanup(3), curl_share_init(3)