diff --git a/src/ioc/db/test/dbChArrTest.cpp b/src/ioc/db/test/dbChArrTest.cpp
index 6451fa35a..8a788bed6 100644
--- a/src/ioc/db/test/dbChArrTest.cpp
+++ b/src/ioc/db/test/dbChArrTest.cpp
@@ -56,11 +56,13 @@ static void createAndOpen(const char *name, dbChannel**pch)
     testOk((ellCount(&(*pch)->post_chain) == 0), "no filters in post chain");
 }
 
+extern "C" {
 static void freeArray(db_field_log *pfl) {
     if (pfl->type == dbfl_type_ref) {
         free(pfl->u.r.field);
     }
 }
+}
 
 static void testHead (const char *title, const char *typ = "") {
     const char *line = "------------------------------------------------------------------------------";
@@ -197,6 +199,7 @@ static void check(short dbr_type) {
 
 static dbEventCtx evtctx;
 
+extern "C" {
 static void dbChArrTestCleanup(void* junk)
 {
     dbFreeBase(pdbbase);
@@ -207,6 +210,7 @@ static void dbChArrTestCleanup(void* junk)
 
     dbmfFreeChunks();
 }
+}
 
 MAIN(dbChArrTest)
 {
diff --git a/src/std/filters/test/arrTest.cpp b/src/std/filters/test/arrTest.cpp
index 3f4fb79c8..026185eac 100644
--- a/src/std/filters/test/arrTest.cpp
+++ b/src/std/filters/test/arrTest.cpp
@@ -54,9 +54,11 @@ extern "C" {
 
 const char *server_port = CA_SERVER_PORT;
 
+extern "C" {
 static void exitSubroutine(subRecord *precord) {
     epicsExit((precord->a == 0.0) ? EXIT_SUCCESS : EXIT_FAILURE);
 }
+}
 
 static int fl_equals_array(short type, const db_field_log *pfl1, void *p2) {
     for (int i = 0; i < pfl1->no_elements; i++) {
@@ -298,6 +300,7 @@ static void check(short dbr_type) {
 
 static dbEventCtx evtctx;
 
+extern "C" {
 static void arrTestCleanup(void* junk)
 {
     dbFreeBase(pdbbase);
@@ -308,6 +311,7 @@ static void arrTestCleanup(void* junk)
 
     dbmfFreeChunks();
 }
+}
 
 MAIN(arrTest)
 {