CURLOPT_RESOLVER_START_FUNCTION - callback called before a new name resolve is started
#include <curl/curl.h> int resolver_start_cb(void *resolver_state, void *reserved, void *userdata); CURLcode curl_easy_setopt(CURL *handle, CURLOPT_RESOLVER_START_FUNCTION, resolver_start_cb);
curl_easy_setopt options CURLOPT_RESOLVER_START_FUNCTION(3)
NAME
CURLOPT_RESOLVER_START_FUNCTION - callback called before a new name
resolve is started
SYNOPSIS
#include <curl/curl.h>
int resolver_start_cb(void *resolver_state, void *reserved, void *userdata);
CURLcode curl_easy_setopt(CURL *handle,
CURLOPT_RESOLVER_START_FUNCTION,
resolver_start_cb);
DESCRIPTION
Pass a pointer to your callback function, which should match the proto-
type shown above.
This callback function gets called by libcurl every time before a new
resolve request is started.
resolver_state points to a backend-specific resolver state. Currently
only the ares resolver backend has a resolver state. It can be used to
set up any desired option on the ares channel before it's used, for
example setting up socket callback options.
reserved is reserved.
userdata is the user pointer set with the CUR-
LOPT_RESOLVER_START_DATA(3) option.
The callback must return 0 on success. Returning a non-zero value will
cause the resolve to fail.
DEFAULT
NULL (No callback)
PROTOCOLS
All
EXAMPLE
static int resolver_start_cb(void *resolver_state, void *reserved,
void *userdata)
{
(void)reserved;
printf("Received resolver_state=%p userdata=%p\n",
resolver_state, userdata);
return 0;
}
CURL *curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_RESOLVER_START_FUNCTION, resolver_start_cb);
curl_easy_setopt(curl, CURLOPT_RESOLVER_START_DATA, curl);
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
AVAILABILITY
Added in 7.59.0
RETURN VALUE
Returns CURLE_OK
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
+---------------+------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+------------------+
|Availability | web/curl |
+---------------+------------------+
|Stability | Uncommitted |
+---------------+------------------+
SEE ALSO
CURLOPT_RESOLVER_START_DATA(3)
NOTES
Source code for open source software components in Oracle Solaris can
be found at https://www.oracle.com/downloads/opensource/solaris-source-
code-downloads.html.
This software was built from source available at
https://github.com/oracle/solaris-userland. The original community
source was downloaded from https://curl.se/down-
load/curl-7.83.1.tar.bz2.
Further information about this software can be found on the open source
community website at http://curl.haxx.se/.
libcurl 7.83.1 September 08, 2021
CURLOPT_RESOLVER_START_FUNCTION(3)