AtomicBoolean for _closed flag

testApp/utils/atomicBooleanTest.cpp

@@ -0,0 +1,16 @@
+#include <gtest/gtest.h>
+
+#include <remote.h>
+
+using namespace epics::pvAccess;
+
+TEST(atomicBooleanTest, atomicBoolean)
+{
+    AtomicBoolean ab;
+
+    EXPECT_FALSE(ab.get());
+    ab.set();
+    EXPECT_TRUE(ab.get());
+    ab.clear();
+    EXPECT_FALSE(ab.get());
+}