From fb742beae3f92b83251814dd000e52d93d4e4995 Mon Sep 17 00:00:00 2001
From: Andrew Johnson <anj@anl.gov>
Date: Fri, 6 Jan 2023 15:24:56 -0600
Subject: [PATCH] Fix epicsThreadOnceTest.c

Replace epicsThreadSleep() with proper thread synchronization.
The main thread was reading runCount without taking lock first.
Taking the lock before accessing doneCount might not be necessary
given the epicsEventMustWait(), but not 100% sure.
---
 modules/libcom/test/epicsThreadOnceTest.c | 25 ++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/modules/libcom/test/epicsThreadOnceTest.c b/modules/libcom/test/epicsThreadOnceTest.c
index 6241e88f6..f48f7571c 100644
--- a/modules/libcom/test/epicsThreadOnceTest.c
+++ b/modules/libcom/test/epicsThreadOnceTest.c
@@ -56,6 +56,17 @@ void onceThread(void *ctx)
     epicsMutexUnlock(lock);
 }
 
+int getRunCount(void)
+{
+    int count;
+
+    epicsMutexMustLock(lock);
+    count = runCount;
+    epicsMutexUnlock(lock);
+
+    return count;
+}
+
 
 void recurseInit(void);
 void onceRecurse(void *ctx)
@@ -77,10 +88,10 @@ void recurseThread(void *ctx)
 
 MAIN(epicsThreadOnceTest)
 {
-    int i;
+    int i, count;
     epicsThreadId tid;
 
-    testPlan(3 + NUM_ONCE_THREADS);
+    testPlan(2 + NUM_ONCE_THREADS);
 
     go = epicsEventMustCreate(epicsEventEmpty);
     done = epicsEventMustCreate(epicsEventEmpty);
@@ -94,13 +105,17 @@ MAIN(epicsThreadOnceTest)
             epicsThreadGetStackSize(epicsThreadStackSmall),
             onceThread, 0);
     }
-    epicsThreadSleep(0.1);
+    while ((count = getRunCount()) < NUM_ONCE_THREADS)
+        epicsThreadSleep(0.1);
 
-    testOk(runCount == NUM_ONCE_THREADS, "runCount = %d", runCount);
     epicsEventSignal(go); /* Use epicsEventBroadcast(go) when available */
     epicsEventMustWait(done);
 
-    testOk(doneCount == NUM_ONCE_THREADS, "doneCount = %d", doneCount);
+    epicsMutexMustLock(lock);
+    count = doneCount;
+    epicsMutexUnlock(lock);
+
+    testOk(count == NUM_ONCE_THREADS, "doneCount = %d", count);
     testDiag("init was run by %s", initBy);
 
     eltc(0);