libcurl-share(3) Introduction to Library Functions libcurl-share(3)

NAME

libcurl-share - how to use the share interface

DESCRIPTION

This is an overview on how to use the libcurl share interface in your
C programs. There are specific man pages for each function mentioned
in here.

All functions in the share interface are prefixed with curl_share.

OBJECTIVES

The share interface was added to enable sharing of data between curl
handles.

ONE SET OF DATA - MANY TRANSFERS
You can have multiple easy handles share data between them. Have them
update and use the same cookie database, DNS cache, TLS session cache
and/or connection cache. This way, each single transfer takes
advantage from data updates made by the other transfer(s).

SHARE OBJECT

You create a shared object with curl_share_init(3). It returns a
handle for a newly created one.

You tell the shared object what data you want it to share by using
curl_share_setopt(3).

Since you can use this share from multiple threads, and libcurl has
no internal thread synchronization, you must provide mutex callbacks
if you are using this multi-threaded. You set lock and unlock
functions with curl_share_setopt(3) too.

Then, you make an easy handle to use this share, you set the
CURLOPT_SHARE(3) option with curl_easy_setopt(3), and pass in share
handle. You can make any number of easy handles share the same share
handle.

To make an easy handle stop using that particular share, you set
CURLOPT_SHARE(3) to NULL for that easy handle. To make a handle stop
sharing a particular data, you can CURLSHOPT_UNSHARE(3) it.

When you are done using the share, make sure that no easy handle is
still using it, and call curl_share_cleanup(3) on the handle.

SEE ALSO

curl_share_cleanup(3), curl_share_init(3), curl_share_setopt(3),
libcurl-easy(3), libcurl-errors(3), libcurl-multi(3)

libcurl 2025-02-25 libcurl-share(3)