CURLOPT_DNS_CACHE_TIMEOUT(3)                          curl_easy_setopt options

NAME
       CURLOPT_DNS_CACHE_TIMEOUT - set 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
       completely 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 don't re-
       read name server information unless explicitly told so (for example, by
       calling _init&section=3">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 doesn't 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 very 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

SEE ALSO
       CURLOPT_DNS_USE_GLOBAL_CACHE(3), CURLOPT_DNS_SERVERS(3),
       CURLOPT_RESOLVE(3),

libcurl 7.77.0                 November 4, 2020   CURLOPT_DNS_CACHE_TIMEOUT(3)