diff --git a/pvDataApp/Makefile b/pvDataApp/Makefile
index a9f84f2..e66a3e1 100644
--- a/pvDataApp/Makefile
+++ b/pvDataApp/Makefile
@@ -108,5 +108,7 @@ LIBSRCS += monitor.cpp
 LIBRARY = pvData
 pvData_LIBS += Com
 
+USR_CXXFLAGS_RTEMS = -D__rtems__
+
 include $(TOP)/configure/RULES
 
diff --git a/pvDataApp/misc/parseToPOD.cpp b/pvDataApp/misc/parseToPOD.cpp
index 2fcf51f..620970d 100644
--- a/pvDataApp/misc/parseToPOD.cpp
+++ b/pvDataApp/misc/parseToPOD.cpp
@@ -14,7 +14,7 @@
 #include "typeCast.h"
 
 // need to use "long long" when sizeof(int)==sizeof(long)
-#if (ULONG_MAX == 0xfffffffful) || defined(_WIN32)
+#if (ULONG_MAX == 0xfffffffful) || defined(_WIN32) || defined(__rtems__)
 #define NEED_LONGLONG
 #endif