From b74718ee37115ce70b36b70a6fd197b8ff86857c Mon Sep 17 00:00:00 2001
From: apnadkarni <apnmbx-wits@yahoo.com>
Date: Mon, 22 Sep 2025 10:34:22 +0000
Subject: Bug [c9e68eb6ca] - Windows version

---
 win/tclWinInit.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/win/tclWinInit.c b/win/tclWinInit.c
index 29e177d..3e4daab 100644
--- a/win/tclWinInit.c
+++ b/win/tclWinInit.c
@@ -221,6 +221,7 @@ AppendEnvironment(
 {
     int pathc;
     WCHAR wBuf[MAX_PATH];
+    DWORD dw;
     char buf[MAX_PATH * 3];
     Tcl_Obj *objPtr;
     Tcl_DString ds;
@@ -245,13 +246,14 @@ AppendEnvironment(
 	Tcl_Panic("no '/' character found in lib");
     }
 
-    /*
-     * The "L" preceding the TCL_LIBRARY string is used to tell VC++ that
-     * this is a Unicode string.
-     */
-
-    GetEnvironmentVariableW(L"TCL_LIBRARY", wBuf, MAX_PATH);
-    WideCharToMultiByte(CP_UTF8, 0, wBuf, -1, buf, MAX_PATH * 3, NULL, NULL);
+    dw = GetEnvironmentVariableW(L"TCL_LIBRARY", wBuf, MAX_PATH);
+    if (dw <= 0 || dw >= (sizeof(buf) / sizeof(buf[0]))) {
+	return;
+    }
+    if (WideCharToMultiByte(
+	    CP_UTF8, 0, wBuf, -1, buf, MAX_PATH * 3, NULL, NULL) == 0) {
+	return;
+    }
 
     if (buf[0] != '\0') {
 	objPtr = Tcl_NewStringObj(buf, -1);
-- 
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