1 files changed, 11 insertions, 3 deletions

diff --git a/CPP/Windows/FileFind.h b/CPP/Windows/FileFind.h
index fcfe02c..11408d0 100644
--- a/CPP/Windows/FileFind.h
+++ b/CPP/Windows/FileFind.h
@@ -1,7 +1,7 @@
 // Windows/FileFind.h
 
-#ifndef __WINDOWS_FILE_FIND_H
-#define __WINDOWS_FILE_FIND_H
+#ifndef ZIP7_INC_WINDOWS_FILE_FIND_H
+#define ZIP7_INC_WINDOWS_FILE_FIND_H
 
 #ifndef _WIN32
 #include <sys/stat.h>
@@ -249,7 +249,15 @@ class CFindChangeNotification  MY_UNCOPYABLE
   HANDLE _handle;
 public:
   operator HANDLE () { return _handle; }
-  bool IsHandleAllocated() const { return _handle != INVALID_HANDLE_VALUE && _handle != 0; }
+  bool IsHandleAllocated() const
+  {
+    /* at least on win2000/XP (undocumented):
+       if pathName is "" or NULL,
+       FindFirstChangeNotification() could return NULL.
+       So we check for INVALID_HANDLE_VALUE and NULL.
+    */
+    return _handle != INVALID_HANDLE_VALUE && _handle != NULL;
+  }
   CFindChangeNotification(): _handle(INVALID_HANDLE_VALUE) {}
   ~CFindChangeNotification() { Close(); }
   bool Close() throw();