If ai uses no conversion, transport long i/o to and from val directly. This preverves more bits on 64 bit systems than going through the 32 bit rval field.

makefile

@@ -1,12 +1,10 @@
 include /ioc/tools/driver.makefile
 EXCLUDE_VERSIONS = 3.13.2
-PROJECT=stream2
+PROJECT=stream
 BUILDCLASSES += Linux
 
 #DOCUDIR = doc
 
-DBDS = stream.dbd
-
 BUSSES  += AsynDriver
 BUSSES  += Dummy
 
@@ -42,9 +40,9 @@ HEADERS += StreamBuffer.h
 HEADERS += StreamError.h
 
 ifeq (${EPICS_BASETYPE},3.13)
-USR_INCLUDES += -include $(INSTALL_INCLUDE)/compat3_13.h
-endif
-ifeq (${EPICS_BASETYPE},3.14)
+# old gcc needs full path for -include
+CXXFLAGS += -include $(foreach d,${INCLUDES:-I%=%},$(wildcard $d/compat3_13.h))
+else
 RECORDTYPES += calcout
 endif
 
@@ -54,5 +52,7 @@ streamReferences:
 	perl ../src/makeref.pl Interface $(BUSSES) > $@
 	perl ../src/makeref.pl Converter $(FORMATS) >> $@
 
-stream.dbd:
+# have to hack a bit to work with both versions of driver.makefile
+DBDFILES = O.$${EPICSVERSION}_$${T_A}/streamSup.dbd
+../O.${EPICSVERSION}_${T_A}/streamSup.dbd:
 	perl ../src/makedbd.pl $(RECORDTYPES) > $@

src/devaiStream.c

@@ -20,6 +20,7 @@
 
 #include "devStream.h"
 #include <aiRecord.h>
+#include <menuConvert.h>
 #include <epicsExport.h>
 
 static long readData (dbCommon *record, format_t *format)
@@ -45,6 +46,11 @@ static long readData (dbCommon *record, format_t *format)
         {
             long rval;
             if (streamScanf (record, format, &rval)) return ERROR;
+            if (ai->linr == menuConvertNO_CONVERSION)
+            {
+                ai->val = (double) rval;
+                return DO_NOT_CONVERT;
+            }
             ai->rval = rval;
             return OK;
         }
@@ -67,6 +73,10 @@ static long writeData (dbCommon *record, format_t *format)
         }
         case DBF_LONG:
         {
+            if (ai->linr == menuConvertNO_CONVERSION)
+            {
+                return streamPrintf (record, format, (long) ai->val);
+            }
             return streamPrintf (record, format, (long) ai->rval);
         }
     }