From bfd3c9fe869cc9bea3ea1def0be063d771138ded Mon Sep 17 00:00:00 2001
From: David Harris <David_Harris@hmc.edu>
Date: Fri, 14 Jun 2024 07:09:53 -0700
Subject: [PATCH] Fixed gettenvval when variable is undefined per verilator
 Issue 5179

---
 sim/verilator/wrapper.c | 4 ++++
 1 file changed, 4 insertions(+)

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));
 }
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