libcurl-share(3) Library Functions Manual 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 CUR-
LOPT_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 CUR-
LOPT_SHARE(3) to NULL for that easy handle. To make a handle stop shar-
ing 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 2026-07-12 libcurl-share(3)
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