From 0fa88efc2b6340180148c3b3307ece1447a9fb7b Mon Sep 17 00:00:00 2001
From: John Regehr <regehr@cs.utah.edu>
Date: Thu, 19 Nov 2020 14:42:55 -0700
Subject: [PATCH] scoped_timer: wait for timer thread before main thread
 continues (#4803)

---
 src/util/scoped_timer.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/util/scoped_timer.cpp b/src/util/scoped_timer.cpp
index 44bf30f4c..33c6a2dc8 100644
--- a/src/util/scoped_timer.cpp
+++ b/src/util/scoped_timer.cpp
@@ -34,7 +34,7 @@ struct scoped_timer_state {
     std::timed_mutex m_mutex;
     event_handler * eh;
     unsigned ms;
-    int work;
+    std::atomic<int> work;
     std::condition_variable_any cv;
 };
 
@@ -102,6 +102,8 @@ public:
 
     ~imp() {
         s->m_mutex.unlock();
+        while (s->work == 1)
+            std::this_thread::yield();
     }
 };