Update networking layer w/ CURL and emscripten impl

2025-11-08 01:50:36 +11:00
parent a17925904d
commit f6874dc55a
4105 changed files with 694617 additions and 179 deletions
@@ -0,0 +1,90 @@
+---
+c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
+SPDX-License-Identifier: curl
+Title: CURLOPT_RESOLVER_START_FUNCTION
+Section: 3
+Source: libcurl
+See-also:
+  - CURLOPT_PREREQFUNCTION (3)
+  - CURLOPT_RESOLVER_START_DATA (3)
+Protocol:
+  - All
+Added-in: 7.59.0
+---
+
+# NAME
+
+CURLOPT_RESOLVER_START_FUNCTION - callback called before a new name resolve is started
+
+# SYNOPSIS
+
+~~~c
+#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)
+
+# %PROTOCOLS%
+
+# EXAMPLE
+
+~~~c
+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);
+  }
+}
+~~~
+
+# %AVAILABILITY%
+
+# RETURN VALUE
+
+curl_easy_setopt(3) returns a CURLcode indicating success or error.
+
+CURLE_OK (0) means everything was OK, non-zero means an error occurred, see
+libcurl-errors(3).