diff --git a/Util/OpenMPReplacement.h b/Util/OpenMPReplacement.h
index 5f99cc28b..232dcbd62 100644
--- a/Util/OpenMPReplacement.h
+++ b/Util/OpenMPReplacement.h
@@ -28,7 +28,7 @@ or see http://www.gnu.org/licenses/agpl.txt.
 inline const int omp_get_num_procs() { return 1; }
 inline const int omp_get_max_threads() { return 1; }
 inline const int omp_get_thread_num() { return 0; }
-inline const int omp_set_num_threads(int i) {}
+inline const void omp_set_num_threads(int i) {}
 #endif
 
 #endif