mirror of
https://github.com/moparisthebest/curl
synced 2024-11-10 19:45:04 -05:00
74 lines
2.8 KiB
Groff
74 lines
2.8 KiB
Groff
.\" **************************************************************************
|
|
.\" * _ _ ____ _
|
|
.\" * Project ___| | | | _ \| |
|
|
.\" * / __| | | | |_) | |
|
|
.\" * | (__| |_| | _ <| |___
|
|
.\" * \___|\___/|_| \_\_____|
|
|
.\" *
|
|
.\" * Copyright (C) 1998 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
|
|
.\" *
|
|
.\" * This software is licensed as described in the file COPYING, which
|
|
.\" * you should have received as part of this distribution. The terms
|
|
.\" * are also available at https://curl.haxx.se/docs/copyright.html.
|
|
.\" *
|
|
.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
|
|
.\" * copies of the Software, and permit persons to whom the Software is
|
|
.\" * furnished to do so, under the terms of the COPYING file.
|
|
.\" *
|
|
.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
|
|
.\" * KIND, either express or implied.
|
|
.\" *
|
|
.\" **************************************************************************
|
|
.\"
|
|
.TH CURLOPT_DNS_CACHE_TIMEOUT 3 "17 Jun 2014" "libcurl 7.37.0" "curl_easy_setopt options"
|
|
.SH NAME
|
|
CURLOPT_DNS_CACHE_TIMEOUT \- set life-time for DNS cache entries
|
|
.SH SYNOPSIS
|
|
#include <curl/curl.h>
|
|
|
|
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DNS_CACHE_TIMEOUT, long age);
|
|
.SH 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
|
|
\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.
|
|
|
|
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.
|
|
.SH DEFAULT
|
|
60
|
|
.SH PROTOCOLS
|
|
All
|
|
.SH EXAMPLE
|
|
.nf
|
|
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);
|
|
}
|
|
.fi
|
|
.SH AVAILABILITY
|
|
Always
|
|
.SH RETURN VALUE
|
|
Returns CURLE_OK
|
|
.SH "SEE ALSO"
|
|
.BR CURLOPT_DNS_USE_GLOBAL_CACHE "(3), " CURLOPT_DNS_SERVERS "(3), "
|
|
.BR CURLOPT_RESOLVE "(3), "
|