From 836fe5dbb072340f3740e77ff2f85e9722c84102 Mon Sep 17 00:00:00 2001
From: Jeff Hill <johill@lanl.gov>
Date: Tue, 26 Mar 2002 01:35:54 +0000
Subject: [PATCH] use epicsThreadOnce so that we are not dependent on static
 member data

---
 src/libCom/cxxTemplates/epicsSingleton.h      |  1 -
 .../cxxTemplates/epicsSingletonBase.cpp       | 22 ++++++++++++++++---
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/src/libCom/cxxTemplates/epicsSingleton.h b/src/libCom/cxxTemplates/epicsSingleton.h
index 5a1fa7b38..472a21ff9 100644
--- a/src/libCom/cxxTemplates/epicsSingleton.h
+++ b/src/libCom/cxxTemplates/epicsSingleton.h
@@ -20,7 +20,6 @@ protected:
     void * singletonPointer () const;
 private:
     void * pSingleton;
-    static class epicsMutex mutex;
     virtual void * factory () = 0;
 };
 
diff --git a/src/libCom/cxxTemplates/epicsSingletonBase.cpp b/src/libCom/cxxTemplates/epicsSingletonBase.cpp
index 4e6c552b0..f2f3a5be8 100644
--- a/src/libCom/cxxTemplates/epicsSingletonBase.cpp
+++ b/src/libCom/cxxTemplates/epicsSingletonBase.cpp
@@ -10,9 +10,22 @@
 #define epicsExportSharedSymbols
 #include "epicsMutex.h"
 #include "epicsGuard.h"
+#include "epicsThread.h"
 #include "epicsSingleton.h"
 
-epicsMutex epicsSingletonBase::mutex;
+static epicsThreadOnceId epicsSingletonOnceId = EPICS_THREAD_ONCE_INIT;
+static epicsMutex *pSingletonBaseMutexEPICS;
+
+static void epicsSingletonCleanup ()
+{
+    delete pSingletonBaseMutexEPICS;
+}
+
+static void epicsSingletonOnce ( void * )
+{
+    pSingletonBaseMutexEPICS = new epicsMutex;
+    atexit ( epicsSingletonCleanup );
+}
 
 epicsSingletonBase::epicsSingletonBase () : pSingleton ( 0 )
 {
@@ -29,8 +42,11 @@ epicsSingletonBase::~epicsSingletonBase ()
 
 void epicsSingletonBase::lockedFactory ()
 {
-    epicsGuard < epicsMutex > guard ( this->mutex );
     if ( ! this->pSingleton ) {
-        this->pSingleton = this->factory ();
+        epicsThreadOnce ( & epicsSingletonOnceId, epicsSingletonOnce, 0 );
+        epicsGuard < epicsMutex > guard ( *pSingletonBaseMutexEPICS );
+        if ( ! this->pSingleton ) {
+            this->pSingleton = this->factory ();
+        }
     }
 }
\ No newline at end of file