From 70a364a92a5a8c24ab93c8ce5d07f4ede405bb4e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?I=C3=B1aki=20=C3=9Acar?= <i.ucar86@gmail.com>
Date: Mon, 22 Jan 2018 18:43:55 +0100
Subject: [PATCH] quick fix

---
 src/udunits.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/udunits.cpp b/src/udunits.cpp
index f46dfede..9b253bd8 100644
--- a/src/udunits.cpp
+++ b/src/udunits.cpp
@@ -39,7 +39,10 @@ void udunits_init(CharacterVector path) {
 }
 
 // [[Rcpp::export]]
-void udunits_exit() { ut_free_system(sys); }
+void udunits_exit() { 
+  ut_free_system(sys);
+  sys = NULL;
+}
 
 // typedef std::vector<void *> ut_vec;