From c448732249b6297b333d6aad51d82767e3135e5b Mon Sep 17 00:00:00 2001
From: Rom Walton <romw@romwnet.org>
Date: Tue, 29 Jan 2013 12:47:26 -0500
Subject: [PATCH] lib: Only process FormatMessage output if the function
 succeeds.  The CC calls windows_format_error_string() for all non-zero
 returns.

---
 lib/win_util.cpp | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/lib/win_util.cpp b/lib/win_util.cpp
index f4aa0e8997..cb213c06ab 100644
--- a/lib/win_util.cpp
+++ b/lib/win_util.cpp
@@ -901,14 +901,16 @@ char* windows_format_error_string(
         NULL
     );
 
-    // convert from current character encoding into UTF8
-    std::string encoded_message = W2A(std::wstring(lpszTemp));
+    if (dwRet != 0) {
+        // convert from current character encoding into UTF8
+        std::string encoded_message = W2A(std::wstring(lpszTemp));
 
-    // include the hex error code as well
-    snprintf(pszBuf, iSize, "%s (0x%x)", encoded_message.c_str(), dwError);
+        // include the hex error code as well
+        snprintf(pszBuf, iSize, "%s (0x%x)", encoded_message.c_str(), dwError);
 
-    if (lpszTemp) {
-        LocalFree((HLOCAL) lpszTemp);
+        if (lpszTemp) {
+            LocalFree((HLOCAL) lpszTemp);
+        }
     }
 
     return pszBuf;