1--- 2c: Copyright (C) Daniel Stenberg, <daniel.se>, et al. 3SPDX-License-Identifier: curl 4Title: libcurl-share 5Section: 3 6Source: libcurl 7See-also: 8 - curl_share_cleanup (3) 9 - curl_share_init (3) 10 - curl_share_setopt (3) 11 - libcurl-easy (3) 12 - libcurl-errors (3) 13 - libcurl-multi (3) 14--- 15 16# NAME 17 18libcurl-share - how to use the share interface 19 20# DESCRIPTION 21 22This is an overview on how to use the libcurl share interface in your C 23programs. There are specific man pages for each function mentioned in 24here. 25 26All functions in the share interface are prefixed with curl_share. 27 28# OBJECTIVES 29 30The share interface was added to enable sharing of data between curl handles. 31 32# ONE SET OF DATA - MANY TRANSFERS 33 34You can have multiple easy handles share data between them. Have them update 35and use the **same** cookie database, DNS cache, TLS session cache and/or 36connection cache! This way, each single transfer takes advantage from data 37updates made by the other transfer(s). 38 39# SHARE OBJECT 40 41You create a shared object with curl_share_init(3). It returns a handle 42for a newly created one. 43 44You tell the shared object what data you want it to share by using 45curl_share_setopt(3). 46 47Since you can use this share from multiple threads, and libcurl has no 48internal thread synchronization, you must provide mutex callbacks if you are 49using this multi-threaded. You set lock and unlock functions with 50curl_share_setopt(3) too. 51 52Then, you make an easy handle to use this share, you set the 53CURLOPT_SHARE(3) option with curl_easy_setopt(3), and pass in 54share handle. You can make any number of easy handles share the same share 55handle. 56 57To make an easy handle stop using that particular share, you set 58CURLOPT_SHARE(3) to NULL for that easy handle. To make a handle stop 59sharing a particular data, you can CURLSHOPT_UNSHARE(3) it. 60 61When you are done using the share, make sure that no easy handle is still using 62it, and call curl_share_cleanup(3) on the handle. 63