diff --git a/include/isam.cpp b/include/isam.cpp
index 8f0de4da8..357fab22e 100755
--- a/include/isam.cpp
+++ b/include/isam.cpp
@@ -1056,6 +1056,18 @@ int TBaseisamfile::_close()
   return err;
 }
 
+int TBaseisamfile::is_valid()
+{ // Ritorna 0 se il file puo' essere aperto senza errori
+  CHECKS(filehnd() == NULL, "File already open ", (const char*)filename());
+  int err = NOERR;
+  getisfd(_isamfile,num()); 
+  if ((filehnd()->fhnd = DB_open(filehnd()->d->SysName,0)) >= 0)
+    DB_close(filehnd()->fhnd);
+  else 
+    err = get_error(filehnd()->fhnd);
+  relisfd(_isamfile);  
+  return err;
+}
 
 ///////////////////////////////////////////////////////////
 // TLocalisamfile
diff --git a/include/isam.h b/include/isam.h
index c4b8c71f0..8c8b2c85a 100755
--- a/include/isam.h
+++ b/include/isam.h
@@ -208,7 +208,7 @@ protected:
   
   void recover();
   int _open(unsigned int mode = _manulock);     // Apre isam file con lock
-  int _close();
+  int _close();        
   const char* filename() const;
 
 public:
@@ -245,6 +245,7 @@ public:
   void indexon();       // Accende gli indici
   void indexoff();      // Spegne gli indici
   int   status() const { return _lasterr; } // Ritorna _lasterr
+  int   is_valid();                         // Ritorna 0 se il file e' valido
   TRectype& curr() const {return *_current;} // Ritorna puntatore a record corrente
   bool eof() const { return status() == _iseof || status() == _isemptyfile;} // Vero se siamo a fine file
   bool bof() const { return status() == _isbof || status() == _isemptyfile;} // Vero se siamo a inizio file