diff --git a/src/include/sph_subs.h b/src/include/sph_subs.h
index 97ea5d0873c1df715c069af076afe7503e1472e1..411a8ec0a0dc4b4e0bd4cb6719d94df4612219e5 100644
--- a/src/include/sph_subs.h
+++ b/src/include/sph_subs.h
@@ -49,9 +49,6 @@ struct C2 {
 	double vsz[2];
 };
 
-//! \brief Write a message to test FORTRAN -> C++ communication
-extern "C" void testme_();
-
 /*! \brief C++ porting of DIEL
  *
  * \param npntmo: `int`