CURLOPT_DNS_CACHE_TIMEOUT - time for DNS cache entries
#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DNS_CACHE_TIMEOUT, long age);
curl_easy_setopt options CURLOPT_DNS_CACHE_TIMEOUT(3) NAME CURLOPT_DNS_CACHE_TIMEOUT - life-time for DNS cache entries SYNOPSIS #include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DNS_CACHE_TIMEOUT, long age); DESCRIPTION Pass a long, this sets the timeout in seconds. Name resolves will be kept in memory and used for this number of seconds. Set to zero to com- pletely disable caching, or set to -1 to make the cached entries remain forever. By default, libcurl caches this info for 60 seconds. The name resolve functions of various libc implementations do not re- read name server information unless explicitly told so (for example, by calling res_init(3)). This may cause libcurl to keep using the older server even if DHCP has updated the server info, and this may look like a DNS cache issue to the casual libcurl-app user. Note that DNS entries have a "TTL" property but libcurl does not use that. This DNS cache timeout is entirely speculative that a name will resolve to the same address for a certain small amount of time into the future. DEFAULT 60 PROTOCOLS All EXAMPLE CURL *curl = curl_easy_init(); if(curl) { curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/foo.bin"); /* only reuse addresses for a short time */ curl_easy_setopt(curl, CURLOPT_DNS_CACHE_TIMEOUT, 2L); ret = curl_easy_perform(curl); /* in this second request, the cache will not be used if more than two seconds have passed since the previous name resolve */ ret = curl_easy_perform(curl); curl_easy_cleanup(curl); } AVAILABILITY Always RETURN VALUE Returns CURLE_OK ATTRIBUTES See attributes(7) for descriptions of the following attributes: +---------------+------------------+ |ATTRIBUTE TYPE | ATTRIBUTE VALUE | +---------------+------------------+ |Availability | web/curl | +---------------+------------------+ |Stability | Uncommitted | +---------------+------------------+ SEE ALSO CURLOPT_DNS_USE_GLOBAL_CACHE(3), CURLOPT_DNS_SERVERS(3), CUR- LOPT_RESOLVE(3), NOTES Source code for open source software components in Oracle Solaris can be found at https://www.oracle.com/downloads/opensource/solaris-source- code-downloads.html. This software was built from source available at https://github.com/oracle/solaris-userland. The original community source was downloaded from https://curl.se/down- load/curl-7.83.1.tar.bz2. Further information about this software can be found on the open source community website at http://curl.haxx.se/. libcurl 7.83.1 November 26, 2021 CURLOPT_DNS_CACHE_TIMEOUT(3)