- always throw an exception in exit

- remove default exit status prints
 - added EXITSTATUS global to enable exit callbacks to determine the status

src/postamble.js

@@ -2,7 +2,6 @@
 // === Auto-generated postamble setup entry stuff ===
 
 var initialStackTop;
-var inMain;
 
 Module['callMain'] = Module.callMain = function callMain(args) {
   assert(runDependencies == 0, 'cannot call main when async dependencies remain! (listen on __ATMAIN__)');
@@ -27,40 +26,36 @@ Module['callMain'] = Module.callMain = function callMain(args) {
   argv.push(0);
   argv = allocate(argv, 'i32', ALLOC_NORMAL);
 
+  initialStackTop = STACKTOP;
+
+  try {
 #if BENCHMARK
-  var start = Date.now();
+    var start = Date.now();
 #endif
 
-  initialStackTop = STACKTOP;
-  inMain = true;
+    var ret = Module['_main'](argc, argv, 0);
 
-  var ret;
-  try {
-    ret = Module['_main'](argc, argv, 0);
+#if BENCHMARK
+    Module.realPrint('main() took ' + (Date.now() - start) + ' milliseconds');
+#endif
+
+    // if we're not running an evented main loop, it's time to exit
+    if (!Module['noExitRuntime']) {
+      exit(ret);
+    }
   }
   catch(e) {
-    if (e && typeof e == 'object' && e.type == 'ExitStatus') {
+    if (e.name == 'ExitStatus') {
       // exit() throws this once it's done to make sure execution
       // has been stopped completely
-      Module.print('Exit Status: ' + e.value);
-      return e.value;
+      return;
     } else if (e == 'SimulateInfiniteLoop') {
       // running an evented main loop, don't immediately exit
       Module['noExitRuntime'] = true;
+      return;
     } else {
       throw e;
     }
-  } finally {
-    inMain = false;
-  }
-
-#if BENCHMARK
-  Module.realPrint('main() took ' + (Date.now() - start) + ' milliseconds');
-#endif
-
-  // if we're not running an evented main loop, it's time to exit
-  if (!Module['noExitRuntime']) {
-    exit(ret);
   }
 }
 
@@ -110,21 +105,21 @@ Module['run'] = Module.run = run;
 
 function exit(status) {
   ABORT = true;
+  EXITSTATUS = status;
   STACKTOP = initialStackTop;
 
-  // TODO call externally added 'exit' callbacks with the status code.
-  // It'd be nice to provide the same interface for all Module events (e.g.
-  // prerun, premain, postmain). Perhaps an EventEmitter so we can do:
-  // Module.on('exit', function (status) {});
-
   // exit the runtime
   exitRuntime();
-
-  if (inMain) {
-    // if we're still inside the callMain's try/catch, we need to throw an
-    // exception in order to immediately terminate execution.
-    throw { type: 'ExitStatus', value: status };
-  }
+ 
+  // throw an exception to halt the current execution
+  function ExitStatus() {
+    this.name = "ExitStatus";
+    this.message = "Program terminated with exit(" + status + ")";
+    this.status = status;
+  };
+  ExitStatus.prototype = new Error();
+  ExitStatus.prototype.constructor = ExitStatus;
+  throw new ExitStatus();
 }
 Module['exit'] = Module.exit = exit;
 
@@ -134,6 +129,7 @@ function abort(text) {
   }
 
   ABORT = true;
+  EXITSTATUS = 1;
 
   throw 'abort() at ' + (new Error().stack);
 }

src/preamble.js

@@ -241,6 +241,7 @@ var setjmpLabels = {};
 #endif
 
 var ABORT = false; // whether we are quitting the application. no code should run after this. set in exit() and abort()
+var EXITSTATUS = 0;
 
 var undef = 0;
 // tempInt is used for 32-bit signed values or smaller. tempBigInt is used

tests/runner.py

@@ -3185,6 +3185,25 @@ Exiting setjmp function, level: 0, prev_jmp: -1
       '''
       self.do_run(src, 'caught std::exception')
 
+    def test_async_exit(self):
+      open('main.c', 'w').write(r'''
+        #include <stdio.h>
+        #include <stdlib.h>
+        #include "emscripten.h"
+
+        void main_loop() {
+          exit(EXIT_SUCCESS);
+        }
+
+        int main() {
+          emscripten_set_main_loop(main_loop, 60, 0);
+          return 0;
+        }
+      ''')
+
+      Popen([PYTHON, EMCC, 'main.c']).communicate()
+      self.assertNotContained('Reached an unreachable!', run_js(self.in_dir('a.out.js'), stderr=STDOUT))
+
     def test_exit_stack(self):
       if self.emcc_args is None: return self.skip('requires emcc')
       if Settings.ASM_JS: return self.skip('uses report_stack without exporting')
@@ -3222,6 +3241,7 @@ Exiting setjmp function, level: 0, prev_jmp: -1
         }
         var Module = {
           postRun: function() {
+            Module.print('Exit Status: ' + EXITSTATUS);
             Module.print('postRun');
             assert(initialStack == STACKTOP, [initialStack, STACKTOP]);
             Module.print('ok.');
@@ -10219,13 +10239,19 @@ def process(filename):
           printf("cleanup\n");
         }
 
-        int main()
-        {
+        int main() {
           atexit(cleanup); // this atexit should still be called
           printf("hello, world!\n");
           exit(118); // Unusual exit status to make sure it's working!
         }
       '''
+      open('post.js', 'w').write('''
+        Module.addOnExit(function () {
+          Module.print('Exit Status: ' + EXITSTATUS);
+        });
+        Module.callMain();
+      ''')
+      self.emcc_args += ['-s', 'INVOKE_RUN=0', '--post-js', 'post.js']
       self.do_run(src, 'hello, world!\ncleanup\nExit Status: 118')
 
     def test_gc(self):