Index: dll/win32/shell32/shellord.cpp
===================================================================
--- dll/win32/shell32/shellord.cpp	(revision 58826)
+++ dll/win32/shell32/shellord.cpp	(working copy)
@@ -1504,8 +1504,8 @@
  *  cchString  [I] size of str.
  *
  * RETURNS
- *     cchString length in the HIWORD;
- *     TRUE in LOWORD if subst was successful and FALSE in other case
+ *     If the expanded string fits the buffer: HIWORD(TRUE), LOWORD (length of expanded string);
+ *     If the expanded string doesn't fit the buffer: HIWORD(FALSE), LOWORD (cchString);
  */
 EXTERN_C DWORD WINAPI DoEnvironmentSubstA(LPSTR pszString, UINT cchString)
 {
@@ -1522,9 +1522,11 @@
             res = TRUE;
             memcpy(pszString, dst, num);
         }
+        else
+            num = cchString;
         HeapFree(GetProcessHeap(), 0, dst);
     }
-    return MAKELONG(res,cchString); /* Always cchString? */
+    return MAKELONG(num,res); 
 }
 
 /************************************************************************
@@ -1545,10 +1547,12 @@
             res = TRUE;
             wcscpy(pszString, dst);
         }
+        else
+            num = cchString;
         HeapFree(GetProcessHeap(), 0, dst);
     }
 
-    return MAKELONG(res,cchString);
+    return MAKELONG(num,res);
 }
 
 /************************************************************************