exit when the wrong args are passed

Makefile

@@ -34,11 +34,6 @@ tags: $(SOURCES)
 $(TARGET): $(OBJS)
 	$(CXX) -o $@ $(CXXFLAGS) $(LDFLAGS) $(OBJS)
 
-
-.PHONY: cclean
-cclean:
-	rm -r build cmake-build-*
-
 print-%: ; @echo '$(subst ','\'',$*=$($*))'
 
 %.o:%.cc

rcpp.cc

@@ -149,6 +149,7 @@ main(int argc, char *argv[])
 	auto regexOptions = std::regex_constants::optimize;
 	if (argc < 4) {
 		std::cerr << "Usage: rcpp pattern files... destination\n";
+		exit(0);
 	}
 
 	auto pattern = std::string(argv[1]);