CURLOPT_DNS_CACHE_TIMEOUT(3)

CURLOPT_DNS_CACHE_TIMEOUT(3curl_easy_setopt optionCURLOPT_DNS_CACHE_TIMEOUT(3)

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  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 specu-
     lative 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, "http://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);
     }

libcurl 7.58.0   Last change: December 09, 2017                 1

CURLOPT_DNS_CACHE_TIMEOUT(3curl_easy_setopt optionCURLOPT_DNS_CACHE_TIMEOUT(3)

AVAILABILITY

     Always

RETURN VALUE

     Returns CURLE_OK

SEE ALSO

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

libcurl 7.58.0   Last change: December 09, 2017                 2