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 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 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

SEE ALSO

       CURLOPT_DNS_USE_GLOBAL_CACHE(3), CURLOPT_DNS_SERVERS(3), CURLOPT_RESOLVE(3),

libcurl 7.81.0                                  November 26, 2021                   CURLOPT_DNS_CACHE_TIMEOUT(3)