diff --git a/sim/verilator/wrapper.c b/sim/verilator/wrapper.c
index 6589a3848..572acaa55 100644
--- a/sim/verilator/wrapper.c
+++ b/sim/verilator/wrapper.c
@@ -3,5 +3,9 @@
 #include "Vtestbench__Dpi.h"
 
 const char *getenvval(const char *pszName) {
+    const char *pszValue = getenv(pszName);
+    if (pszValue == NULL) {
+        return "";
+    }
     return ((const char *) getenv(pszName));
 }
\ No newline at end of file