5 files changed, 18 insertions, 0 deletions
diff --git a/src/library.js b/src/library.js
index d41498b1..f69b52e5 100644
--- a/src/library.js
+++ b/src/library.js
@@ -7517,6 +7517,7 @@ LibraryManager.library = {
       } else {
         {{{ makeSetValue('ai', C_STRUCTS.addrinfo.ai_addrlen, C_STRUCTS.sockaddr_in.__size__, 'i32') }}};
       }
+      {{{ makeSetValue('ai', C_STRUCTS.addrinfo.ai_next, '0', 'i32') }}};
 
       return ai;
     }
diff --git a/src/library_browser.js b/src/library_browser.js
index 5d53b867..d6526d9c 100644
--- a/src/library_browser.js
+++ b/src/library_browser.js
@@ -675,6 +675,8 @@ mergeInto(LibraryManager.library, {
   },
 
   emscripten_async_prepare: function(file, onload, onerror) {
+    Module['noExitRuntime'] = true;
+
     var _file = Pointer_stringify(file);
     var data = FS.analyzePath(_file);
     if (!data.exists) return -1;
@@ -694,6 +696,8 @@ mergeInto(LibraryManager.library, {
   },
 
   emscripten_async_prepare_data: function(data, size, suffix, arg, onload, onerror) {
+    Module['noExitRuntime'] = true;
+
     var _suffix = Pointer_stringify(suffix);
     if (!Browser.asyncPrepareDataCounter) Browser.asyncPrepareDataCounter = 0;
     var name = 'prepare_data_' + (Browser.asyncPrepareDataCounter++) + '.' + _suffix;
@@ -954,6 +958,8 @@ mergeInto(LibraryManager.library, {
   },
 
   emscripten_call_worker: function(id, funcName, data, size, callback, arg) {
+    Module['noExitRuntime'] = true; // should we only do this if there is a callback?
+
     funcName = Pointer_stringify(funcName);
     var info = Browser.workers[id];
     var callbackId = -1;
diff --git a/src/postamble.js b/src/postamble.js
index 90a86474..382d3117 100644
--- a/src/postamble.js
+++ b/src/postamble.js
@@ -202,6 +202,10 @@ if (Module['noInitialRun']) {
   shouldRunNow = false;
 }
 
+#if NO_EXIT_RUNTIME
+Module["noExitRuntime"] = true;
+#endif
+
 run();
 
 // {{POST_RUN_ADDITIONS}}
diff --git a/src/preamble.js b/src/preamble.js
index 25ef1fb3..5038e9c4 100644
--- a/src/preamble.js
+++ b/src/preamble.js
@@ -1027,6 +1027,11 @@ function preMain() {
 }
 
 function exitRuntime() {
+#if ASSERTIONS
+  if (ENVIRONMENT_IS_WEB || ENVIRONMENT_IS_WORKER) {
+    Module.printErr('Exiting runtime. Any attempt to access the compiled C code may fail from now. If you want to keep the runtime alive, set Module["noExitRuntime"] = true or build with -s NO_EXIT_RUNTIME=1');
+  }
+#endif
   callRuntimeCallbacks(__ATEXIT__);
 }
 
diff --git a/src/settings.js b/src/settings.js
index 79e949fa..1db91dca 100644
--- a/src/settings.js
+++ b/src/settings.js
@@ -48,6 +48,8 @@ var VERBOSE = 0; // When set to 1, will generate more verbose output during comp
 var INVOKE_RUN = 1; // Whether we will run the main() function. Disable if you embed the generated
                     // code in your own, and will call main() yourself at the right time (which you
                     // can do with Module.callMain(), with an optional parameter of commandline args).
+var NO_EXIT_RUNTIME = 0; // If set, the runtime is not quit when main() completes (allowing code to
+                         // run afterwards, for example from the browser main event loop).
 var INIT_HEAP = 0; // Whether to initialize memory anywhere other than the stack to 0.
 var TOTAL_STACK = 5*1024*1024; // The total stack size. There is no way to enlarge the stack, so this
                                // value must be large enough for the program's requirements. If