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Updated: Thursday, June 13, 2019
 
 

CURLOPT_RESOLVER_START_FUNCTION (3)

Name

CURLOPT_RESOLVER_START_FUNCTION - set callback to be called before a new resolve request 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

curl_easy_setopt options                    CURLOPT_RESOLVER_START_FUNCTION(3)



NAME
       CURLOPT_RESOLVER_START_FUNCTION  -  set  callback to be called before a
       new resolve request 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, "http://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
       This     software     was    built    from    source    available    at
       https://github.com/oracle/solaris-userland.   The  original   community
       source    was    downloaded    from    https://github.com/curl/curl/ar-
       chive/curl-7_64_0.zip

       Further information about this software can be found on the open source
       community website at http://curl.haxx.se/.



libcurl 7.59.0                    14 Feb 2018
                                            CURLOPT_RESOLVER_START_FUNCTION(3)