diff --git a/src/messages/initialize.cc b/src/messages/initialize.cc
index e80b09d8a..88eae51f4 100644
--- a/src/messages/initialize.cc
+++ b/src/messages/initialize.cc
@@ -242,6 +242,7 @@ void *Indexer(void *arg_) {
   std::string name = "indexer" + std::to_string(idx);
   set_thread_name(name.c_str());
   pipeline::Indexer_Main(h->manager, h->vfs, h->project, h->wfiles);
+  pipeline::ThreadLeave();
   return nullptr;
 }
 } // namespace
@@ -365,7 +366,6 @@ void MessageHandler::shutdown(EmptyParam &, ReplyOnce &reply) {
 }
 
 void MessageHandler::exit(EmptyParam &) {
-  // FIXME cancel threads
-  ::exit(0);
+  pipeline::quit = true;
 }
 } // namespace ccls
diff --git a/src/pipeline.cc b/src/pipeline.cc
index ab6fd2e16..c3c96e74d 100644
--- a/src/pipeline.cc
+++ b/src/pipeline.cc
@@ -77,6 +77,7 @@ void StandaloneInitialize(MessageHandler &, const std::string &root);
 
 namespace pipeline {
 
+std::atomic<bool> quit;
 std::atomic<int64_t> loaded_ts = ATOMIC_VAR_INIT(0),
                      pending_index_requests = ATOMIC_VAR_INIT(0);
 int64_t tick = 0;
@@ -91,6 +92,10 @@ struct Index_Request {
   int64_t ts = tick++;
 };
 
+std::mutex thread_mtx;
+std::condition_variable no_pending_threads;
+int pending_threads;
+
 MultiQueueWaiter *main_waiter;
 MultiQueueWaiter *indexer_waiter;
 MultiQueueWaiter *stdout_waiter;
@@ -361,8 +366,31 @@ bool Indexer_Parse(SemaManager *completion, WorkingFiles *wfiles,
   return true;
 }
 
+void Quit(SemaManager &manager) {
+  quit = true;
+  manager.Quit();
+
+  { std::lock_guard lock(index_request->mutex_); }
+  indexer_waiter->cv.notify_all();
+  { std::lock_guard lock(for_stdout->mutex_); }
+  stdout_waiter->cv.notify_one();
+  std::unique_lock lock(thread_mtx);
+  no_pending_threads.wait(lock, [] { return !pending_threads; });
+}
+
 } // namespace
 
+void ThreadEnter() {
+  std::lock_guard lock(thread_mtx);
+  pending_threads++;
+}
+
+void ThreadLeave() {
+  std::lock_guard lock(thread_mtx);
+  if (!--pending_threads)
+    no_pending_threads.notify_one();
+}
+
 void Init() {
   main_waiter = new MultiQueueWaiter;
   on_request = new ThreadedQueue<InMessage>(main_waiter);
@@ -380,7 +408,8 @@ void Indexer_Main(SemaManager *manager, VFS *vfs, Project *project,
   GroupMatch matcher(g_config->index.whitelist, g_config->index.blacklist);
   while (true)
     if (!Indexer_Parse(manager, wfiles, project, vfs, matcher))
-      indexer_waiter->Wait(index_request);
+      if (indexer_waiter->Wait(quit, index_request))
+        break;
 }
 
 void Main_OnIndexed(DB *db, WorkingFiles *wfiles, IndexUpdate *update) {
@@ -419,6 +448,7 @@ void Main_OnIndexed(DB *db, WorkingFiles *wfiles, IndexUpdate *update) {
 }
 
 void LaunchStdin() {
+  ThreadEnter();
   std::thread([]() {
     set_thread_name("stdin");
     std::string str;
@@ -469,12 +499,13 @@ void LaunchStdin() {
       if (method == "exit")
         break;
     }
-  })
-      .detach();
+  }).detach();
+  ThreadLeave();
 }
 
 void LaunchStdout() {
-  std::thread([=]() {
+  ThreadEnter();
+  std::thread([]() {
     set_thread_name("stdout");
 
     while (true) {
@@ -483,10 +514,11 @@ void LaunchStdout() {
         llvm::outs() << "Content-Length: " << s.size() << "\r\n\r\n" << s;
         llvm::outs().flush();
       }
-      stdout_waiter->Wait(for_stdout);
+      if (stdout_waiter->Wait(quit, for_stdout))
+        break;
     }
-  })
-      .detach();
+  }).detach();
+  ThreadLeave();
 }
 
 void MainLoop() {
@@ -540,16 +572,20 @@ void MainLoop() {
       Main_OnIndexed(&db, &wfiles, &*update);
     }
 
-    if (did_work)
+    if (did_work) {
       has_indexed |= indexed;
-    else {
+      if (quit)
+        break;
+    } else {
       if (has_indexed) {
         FreeUnusedMemory();
         has_indexed = false;
       }
-      main_waiter->Wait(on_indexed, on_request);
+      main_waiter->Wait(quit, on_indexed, on_request);
     }
   }
+
+  Quit(manager);
 }
 
 void Standalone(const std::string &root) {
@@ -590,6 +626,7 @@ void Standalone(const std::string &root) {
   }
   if (tty)
     puts("");
+  Quit(manager);
 }
 
 void Index(const std::string &path, const std::vector<const char *> &args,
diff --git a/src/pipeline.hh b/src/pipeline.hh
index e70d9dd8e..da6b44bc3 100644
--- a/src/pipeline.hh
+++ b/src/pipeline.hh
@@ -36,8 +36,12 @@ enum class IndexMode {
 };
 
 namespace pipeline {
+extern std::atomic<bool> quit;
 extern std::atomic<int64_t> loaded_ts, pending_index_requests;
 extern int64_t tick;
+
+void ThreadEnter();
+void ThreadLeave();
 void Init();
 void LaunchStdin();
 void LaunchStdout();
diff --git a/src/platform.hh b/src/platform.hh
index 076860f57..12446263b 100644
--- a/src/platform.hh
+++ b/src/platform.hh
@@ -19,6 +19,7 @@ limitations under the License.
 #include <string_view>
 #include <vector>
 
+namespace ccls {
 std::string NormalizePath(const std::string &path);
 
 // Free any unused memory and return it to the system.
@@ -31,3 +32,4 @@ std::string GetExternalCommandOutput(const std::vector<std::string> &command,
                                      std::string_view input);
 
 void SpawnThread(void *(*fn)(void *), void *arg);
+} // namespace ccls
diff --git a/src/platform_posix.cc b/src/platform_posix.cc
index 9dd79726c..35d8d271f 100644
--- a/src/platform_posix.cc
+++ b/src/platform_posix.cc
@@ -42,8 +42,16 @@ limitations under the License.
 #include <llvm/ADT/SmallString.h>
 #include <llvm/Support/Path.h>
 
+#include <atomic>
+#include <condition_variable>
+#include <mutex>
 #include <string>
 
+namespace ccls {
+namespace pipeline {
+void ThreadEnter();
+}
+
 std::string NormalizePath(const std::string &path) {
   llvm::SmallString<256> P(path);
   llvm::sys::path::remove_dots(P, true);
@@ -113,14 +121,15 @@ void SpawnThread(void *(*fn)(void *), void *arg) {
   pthread_attr_t attr;
   struct rlimit rlim;
   size_t stack_size = 4 * 1024 * 1024;
-  if (getrlimit(RLIMIT_STACK, &rlim) == 0 &&
-      rlim.rlim_cur != RLIM_INFINITY)
+  if (getrlimit(RLIMIT_STACK, &rlim) == 0 && rlim.rlim_cur != RLIM_INFINITY)
     stack_size = rlim.rlim_cur;
   pthread_attr_init(&attr);
   pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
   pthread_attr_setstacksize(&attr, stack_size);
+  pipeline::ThreadEnter();
   pthread_create(&thd, &attr, fn, arg);
   pthread_attr_destroy(&attr);
 }
+} // namespace ccls
 
 #endif
diff --git a/src/platform_win.cc b/src/platform_win.cc
index 31ba74e93..a2ca5185a 100644
--- a/src/platform_win.cc
+++ b/src/platform_win.cc
@@ -30,6 +30,7 @@ limitations under the License.
 #include <string>
 #include <thread>
 
+namespace ccls {
 std::string NormalizePath(const std::string &path) {
   DWORD retval = 0;
   TCHAR buffer[MAX_PATH] = TEXT("");
@@ -64,5 +65,6 @@ std::string GetExternalCommandOutput(const std::vector<std::string> &command,
 void SpawnThread(void *(*fn)(void *), void *arg) {
   std::thread(fn, arg).detach();
 }
+}
 
 #endif
diff --git a/src/sema_manager.cc b/src/sema_manager.cc
index f5dee4119..a077192d5 100644
--- a/src/sema_manager.cc
+++ b/src/sema_manager.cc
@@ -18,6 +18,7 @@ limitations under the License.
 #include "clang_tu.hh"
 #include "filesystem.hh"
 #include "log.hh"
+#include "pipeline.hh"
 #include "platform.hh"
 
 #include <clang/Lex/PreprocessorOptions.h>
@@ -403,6 +404,8 @@ void *PreambleMain(void *manager_) {
   set_thread_name("preamble");
   while (true) {
     SemaManager::PreambleTask task = manager->preamble_tasks.Dequeue();
+    if (pipeline::quit)
+      break;
 
     bool created = false;
     std::shared_ptr<Session> session =
@@ -424,6 +427,7 @@ void *PreambleMain(void *manager_) {
         manager->ScheduleDiag(task.path, debounce);
     }
   }
+  pipeline::ThreadLeave();
   return nullptr;
 }
 
@@ -432,6 +436,8 @@ void *CompletionMain(void *manager_) {
   set_thread_name("comp");
   while (true) {
     std::unique_ptr<SemaManager::CompTask> task = manager->comp_tasks.Dequeue();
+    if (pipeline::quit)
+      break;
 
     // Drop older requests if we're not buffering.
     while (g_config->completion.dropOldRequests &&
@@ -440,6 +446,8 @@ void *CompletionMain(void *manager_) {
       task->Consumer.reset();
       task->on_complete(nullptr);
       task = manager->comp_tasks.Dequeue();
+      if (pipeline::quit)
+        break;
     }
 
     std::shared_ptr<Session> session = manager->EnsureSession(task->path);
@@ -480,6 +488,7 @@ void *CompletionMain(void *manager_) {
 
     task->on_complete(&Clang->getCodeCompletionConsumer());
   }
+  pipeline::ThreadLeave();
   return nullptr;
 }
 
@@ -516,6 +525,8 @@ void *DiagnosticMain(void *manager_) {
   set_thread_name("diag");
   while (true) {
     SemaManager::DiagTask task = manager->diag_tasks.Dequeue();
+    if (pipeline::quit)
+      break;
     int64_t wait = task.wait_until -
                    chrono::duration_cast<chrono::milliseconds>(
                        chrono::high_resolution_clock::now().time_since_epoch())
@@ -627,6 +638,7 @@ void *DiagnosticMain(void *manager_) {
     }
     manager->on_diagnostic_(task.path, ls_diags);
   }
+  pipeline::ThreadLeave();
   return nullptr;
 }
 
@@ -704,4 +716,10 @@ void SemaManager::Clear() {
   std::lock_guard lock(mutex);
   sessions.Clear();
 }
+
+void SemaManager::Quit() {
+  comp_tasks.PushBack(nullptr);
+  diag_tasks.PushBack({});
+  preamble_tasks.PushBack({});
+}
 } // namespace ccls
diff --git a/src/sema_manager.hh b/src/sema_manager.hh
index 632b2eaa0..5d5733492 100644
--- a/src/sema_manager.hh
+++ b/src/sema_manager.hh
@@ -148,7 +148,8 @@ struct SemaManager {
   void OnClose(const std::string &path);
   std::shared_ptr<ccls::Session> EnsureSession(const std::string &path,
                                                bool *created = nullptr);
-  void Clear(void);
+  void Clear();
+  void Quit();
 
   // Global state.
   Project *project_;
diff --git a/src/threaded_queue.hh b/src/threaded_queue.hh
index ced88be43..d8846e191 100644
--- a/src/threaded_queue.hh
+++ b/src/threaded_queue.hh
@@ -66,10 +66,15 @@ struct MultiQueueWaiter {
     return false;
   }
 
-  template <typename... BaseThreadQueue> void Wait(BaseThreadQueue... queues) {
+  template <typename... BaseThreadQueue>
+  bool Wait(std::atomic<bool> &quit, BaseThreadQueue... queues) {
     MultiQueueLock<BaseThreadQueue...> l(queues...);
-    while (!HasState({queues...}))
+    while (!quit) {
+      if (HasState({queues...}))
+        return false;
       cv.wait(l);
+    }
+    return true;
   }
 };