diff --git a/source/Makefile b/source/Makefile
index aefe4010..2a5576c6 100644
--- a/source/Makefile
+++ b/source/Makefile
@@ -535,7 +535,7 @@ check-style:
 		var=`clang-format "$$src" | diff "$$src" - | wc -l` ; \
 		if [ $$var -ne 0 ] ; then \
 			echo "$$src does not respect the coding style (diff: $$var lines)" ; \
-			clang-format "$$src" | diff "$$src" - \
+			clang-format "$$src" | diff "$$src" ; \
 			exit 1 ; \
 		fi ; \
 	done