diff --git a/samples/sockets/Makefile.in b/samples/sockets/Makefile.in
index 1a2e1fd3cc..6b12993eca 100644
--- a/samples/sockets/Makefile.in
+++ b/samples/sockets/Makefile.in
@@ -21,7 +21,7 @@ VPATH = @PATH_IFS@$(top_srcdir)/samples/sockets # ':' for autoconf
 .SUFFIXES:	.o .cpp .c .cxx
 
 .cpp.o :
-	$(CC) -c $(CPPFLAGS) -o $@ $<
+	$(CC) -c $(CXXFLAGS) -o $@ $<
 
 # Set defaults from configure
 include ../../src/make.env