From 2814c779bd9c3f13e70b95df40c9aa3320272028 Mon Sep 17 00:00:00 2001
From: Michael Davidsaver <mdavidsaver@gmail.com>
Date: Tue, 15 Jan 2019 20:53:01 -0800
Subject: [PATCH] StandardField::getStandardField safety

---
 src/factory/StandardField.cpp | 21 +++++++++++++--------
 src/pv/standardField.h        |  1 +
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/src/factory/StandardField.cpp b/src/factory/StandardField.cpp
index 9e1c972..4bfc7f3 100644
--- a/src/factory/StandardField.cpp
+++ b/src/factory/StandardField.cpp
@@ -11,6 +11,7 @@
 #include <stdexcept>
 
 #include <epicsMutex.h>
+#include <epicsThread.h>
 
 #define epicsExportSharedSymbols
 #include <pv/lock.h>
@@ -262,17 +263,21 @@ StructureConstPtr StandardField::enumerated(string  const &properties)
     return createProperties("epics:nt/NTEnum:1.0",field,properties);
 }
 
+static StandardFieldPtr *stdFieldGbl;
+
+static epicsThreadOnceId stdFieldGblOnce = EPICS_THREAD_ONCE_INIT;
+
+void StandardField::once(void*)
+{
+    stdFieldGbl = new StandardFieldPtr;
+    stdFieldGbl->reset(new StandardField);
+}
+
 const StandardFieldPtr &StandardField::getStandardField()
 {
-    static StandardFieldPtr standardFieldCreate;
-    static Mutex mutex;
-    Lock xx(mutex);
+    epicsThreadOnce(&stdFieldGblOnce, &StandardField::once, 0);
 
-    if(standardFieldCreate.get()==0)
-    {
-        standardFieldCreate = StandardFieldPtr(new StandardField());
-    }
-    return standardFieldCreate;
+    return *stdFieldGbl;
 }
 
 }}
diff --git a/src/pv/standardField.h b/src/pv/standardField.h
index 3dfd095..fe4a8ac 100644
--- a/src/pv/standardField.h
+++ b/src/pv/standardField.h
@@ -61,6 +61,7 @@ typedef std::tr1::shared_ptr<StandardField> StandardFieldPtr;
  * }
  */
 class epicsShareClass StandardField {
+    static void once(void*);
 public:
     /** 
      * getStandardField returns the singleton.