Daniel Stenberg 8c1d9378ac

curldown: make 'added-in:' a mandatory header field

- generate AVAILABILITY manpage sections automatically - for consistent
  wording

- allows us to double-check against other documumentation (symbols-in-versions
  etc)

- enables proper automation/scripting based on this data

- lots of them were wrong or missing in the manpages

- several of them repeated (sometimes mismatching) backend support info

Add test 1488 to verify "added-in" version numbers against
symbols-in-versions.

Closes #14217

2024-07-18 18:04:09 +02:00

1.9 KiB

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SPDX-License-Identifier

Title

Section

Source

See-also

Protocol

Added-in

curl

CURLOPT_RESOLVER_START_FUNCTION

libcurl

CURLOPT_PREREQFUNCTION (3)

CURLOPT_RESOLVER_START_DATA (3)

All

7.59.0

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 prototype 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 is used, for example setting up socket callback options.

reserved is reserved.

userdata is the user pointer set with the CURLOPT_RESOLVER_START_DATA(3) option.

The callback must return 0 on success. Returning a non-zero value causes the resolve to fail.

DEFAULT

NULL (No callback)

EXAMPLE

static int start_cb(void *resolver_state, void *reserved,
                    void *userdata)
{
  (void)reserved;
  printf("Received resolver_state=%p userdata=%p\n",
         resolver_state, userdata);
  return 0;
}

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_RESOLVER_START_FUNCTION, 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);
  }
}

RETURN VALUE

Returns CURLE_OK

1.9 KiB Raw Blame History