diff --git a/src/btstack_memory.c b/src/btstack_memory.c
index 54bb69871..917f70e86 100644
--- a/src/btstack_memory.c
+++ b/src/btstack_memory.c
@@ -56,7 +56,7 @@
 #include <stdlib.h>
 
 #ifdef ENABLE_MALLOC_TEST
-extern "C" void * test_malloc(size_t size);
+void * test_malloc(size_t size);
 #define malloc test_malloc
 #endif
 
diff --git a/tool/btstack_memory_generator.py b/tool/btstack_memory_generator.py
index f2a17d54a..3088d0fb4 100755
--- a/tool/btstack_memory_generator.py
+++ b/tool/btstack_memory_generator.py
@@ -139,7 +139,7 @@ cfile_header_begin = """
 #include <stdlib.h>
 
 #ifdef ENABLE_MALLOC_TEST
-extern "C" void * test_malloc(size_t size);
+void * test_malloc(size_t size);
 #define malloc test_malloc
 #endif