diff --git a/app/paint/Makefile.am b/app/paint/Makefile.am
index 149edba289..c0567061b4 100644
--- a/app/paint/Makefile.am
+++ b/app/paint/Makefile.am
@@ -60,7 +60,7 @@ libapppaint_a_sources = \
 	gimpmybrushsurface.h		\
 	gimppaintcore.c			\
 	gimppaintcore.h			\
-	gimppaintcore-loops.c		\
+	gimppaintcore-loops.cc		\
 	gimppaintcore-loops.h		\
 	gimppaintcore-stroke.c		\
 	gimppaintcore-stroke.h		\
diff --git a/app/paint/gimppaintcore-loops.c b/app/paint/gimppaintcore-loops.cc
similarity index 99%
rename from app/paint/gimppaintcore-loops.c
rename to app/paint/gimppaintcore-loops.cc
index b6b60fc196..8da1a6f264 100644
--- a/app/paint/gimppaintcore-loops.c
+++ b/app/paint/gimppaintcore-loops.cc
@@ -20,6 +20,9 @@
 #include <gegl.h>
 #include <gdk-pixbuf/gdk-pixbuf.h>
 
+extern "C"
+{
+
 #include "paint-types.h"
 
 #include "operations/layer-modes/gimp-layer-modes.h"
@@ -436,3 +439,5 @@ mask_components_onto (GeglBuffer        *src_buffer,
         }
     }
 }
+
+} /* extern "C" */