mirror of
https://codeberg.org/kiss-community/repo
synced 2024-09-11 23:30:13 +00:00
69 lines
2.2 KiB
Groff
69 lines
2.2 KiB
Groff
.\" generated by cd2nroff 0.1 from CURLOPT_DNS_CACHE_TIMEOUT.md
|
|
.TH CURLOPT_DNS_CACHE_TIMEOUT 3 "2024-06-01" libcurl
|
|
.SH NAME
|
|
CURLOPT_DNS_CACHE_TIMEOUT \- life\-time for DNS cache entries
|
|
.SH SYNOPSIS
|
|
.nf
|
|
#include <curl/curl.h>
|
|
|
|
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DNS_CACHE_TIMEOUT, long age);
|
|
.fi
|
|
.SH DESCRIPTION
|
|
Pass a long, this sets the timeout in seconds. Name resolve results are 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.
|
|
|
|
We recommend users not to tamper with this option unless strictly necessary.
|
|
If you do, be careful of using large values that can make the cache size grow
|
|
significantly if many different hostnames are used within that timeout period.
|
|
|
|
The name resolve functions of various libc implementations do not re\-read name
|
|
server information unless explicitly told so (for example, by calling
|
|
\fIres_init(3)\fP). 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.
|
|
|
|
DNS entries have a "TTL" property but libcurl does not use that. This DNS
|
|
cache timeout is entirely speculative that a name resolves to the same address
|
|
for a small amount of time into the future.
|
|
|
|
Since version 8.1.0, libcurl prunes entries from the DNS cache if it exceeds
|
|
30,000 entries no matter which timeout value is used.
|
|
.SH DEFAULT
|
|
60
|
|
.SH PROTOCOLS
|
|
All
|
|
.SH EXAMPLE
|
|
.nf
|
|
int main(void)
|
|
{
|
|
CURL *curl = curl_easy_init();
|
|
if(curl) {
|
|
CURLcode res;
|
|
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);
|
|
|
|
res = curl_easy_perform(curl);
|
|
|
|
/* in this second request, the cache is not be used if more than
|
|
two seconds have passed since the previous name resolve */
|
|
res = curl_easy_perform(curl);
|
|
|
|
curl_easy_cleanup(curl);
|
|
}
|
|
}
|
|
.fi
|
|
.SH AVAILABILITY
|
|
Always
|
|
.SH RETURN VALUE
|
|
Returns CURLE_OK
|
|
.SH SEE ALSO
|
|
.BR CURLOPT_CONNECTTIMEOUT_MS (3),
|
|
.BR CURLOPT_DNS_SERVERS (3),
|
|
.BR CURLOPT_DNS_USE_GLOBAL_CACHE (3),
|
|
.BR CURLOPT_MAXAGE_CONN (3),
|
|
.BR CURLOPT_RESOLVE (3)
|