diff --git a/examples/osd/opentrigger-board/sketch.h b/examples/osd/opentrigger-board/sketch.h
index 383b1ec7f..5616a1651 100644
--- a/examples/osd/opentrigger-board/sketch.h
+++ b/examples/osd/opentrigger-board/sketch.h
@@ -1,6 +1,9 @@
 #ifndef __SKETCH_h__
 #define __SKETCH_h__
 
+#ifdef __cplusplus
+extern "C" 
+#endif
 int color_rgb_from_string (const char *r, const char *g, const char *b);
 
 #endif
diff --git a/examples/osd/opentrigger-board/sketch.pde b/examples/osd/opentrigger-board/sketch.pde
index 9bf39fc2b..a4b1d3767 100755
--- a/examples/osd/opentrigger-board/sketch.pde
+++ b/examples/osd/opentrigger-board/sketch.pde
@@ -76,8 +76,8 @@ color_from_string (const char *name, const char *uri, const char *s)
     leds.setColorRGB(0,color_rgb [0], color_rgb [1], color_rgb [2]);
     return 0;
 }
-
-int 
+ 
+extern "C" int 
 color_rgb_from_string (const char *r, const char *g, const char *b)
 {
     color_rgb [0] = atoi (r);