curl/docs/libcurl/curl_share_setopt.3

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.TH curl_share_setopt 3 "8 Aug 2003" "libcurl 7.10.7" "libcurl Manual"
.SH NAME
curl_share_setopt - Set options for a shared object
.SH SYNOPSIS
.B #include <curl/curl.h>
.sp
CURLSHcode curl_share_setopt(CURLSH *share, CURLSHoption option, parameter);
.ad
.SH DESCRIPTION
Set the \fIoption\fP to \fIparameter\fP for the given \fIshare\fP.
.SH OPTIONS
.IP CURLSHOPT_LOCKFUNC
The \fIparameter\fP 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 \fIdata\fP argument tells what kind of data libcurl wants to lock. Make
sure that the callback uses a different lock for each kind of data.

\fIaccess\fP defines what access type libcurl wants, shared or single.

\fIuserptr\fP is the pointer you set with \fICURLSHOPT_USERDATA\fP.
.IP CURLSHOPT_UNLOCKFUNC
The \fIparameter\fP must be a pointer to a function matching the following
prototype:

void unlock_function(CURL *handle, curl_lock_data data, void *userptr);

\fIdata\fP 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.

\fIuserptr\fP is the pointer you set with \fICURLSHOPT_USERDATA\fP.
.IP CURLSHOPT_SHARE
The \fIparameter\fP specifies a type of data that should be shared. This may
be set to one of the values described below.
.RS
.IP CURL_LOCK_DATA_COOKIE
Cookie data will be shared across the easy handles using this shared object.
Note that this does not activate an easy handle's cookie handling. You can do
that separately by using \fICURLOPT_COOKIEFILE(3)\fP for example.
.IP 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.
.IP 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.
.IP 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 \fBCURL_LOCK_DATA_CONNECT\fP 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.
.IP 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.

\fBCURL_LOCK_DATA_PSL\fP 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.
.RE
.IP CURLSHOPT_UNSHARE
This option does the opposite of \fICURLSHOPT_SHARE\fP. It specifies that
the specified \fIparameter\fP will no longer be shared. Valid values are
the same as those for \fICURLSHOPT_SHARE\fP.
.IP CURLSHOPT_USERDATA
The \fIparameter\fP allows you to specify a pointer to data that will be passed
to the lock_function and unlock_function each time it is called.
.SH RETURN VALUE
CURLSHE_OK (zero) means that the option was set properly, non-zero means an
error occurred as \fI<curl/curl.h>\fP defines. See the \fIlibcurl-errors.3\fP
man page for the full list with descriptions.
.SH "SEE ALSO"
.BR curl_share_cleanup "(3), " curl_share_init "(3)"