libcurl-share - how to use the share interface
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.
The share interface was added to enable sharing of data between curl
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 will take advantage from data
updates made by the other transfer(s).
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
Since you can use this share from multiple threads, and libcurl has no internal
thread synchronization, you must provide mutex callbacks if you're using this
multi-threaded. You set lock and unlock functions with
Then, you make an easy handle to use this share, you set the
option with curl_easy_setopt(3)
, and pass in
share handle. You can make any number of easy handles share the same share
To make an easy handle stop using that particular share, you set
to NULL for that easy handle. To make a handle stop
sharing a particular data, you can CURLSHOPT_UNSHARE
When you're done using the share, make sure that no easy handle is still using
it, and call curl_share_cleanup(3)
on the handle.