diff --git a/include/files.cpp b/include/files.cpp
index 7b6d000ba..6120e4ded 100755
--- a/include/files.cpp
+++ b/include/files.cpp
@@ -13,6 +13,7 @@
 #endif
 
 #include <extcdecl.h>
+#include <lffiles.h>
 
 #define BLOCKLEN 512
 #define INVFLD    255
@@ -366,7 +367,41 @@ TTrec::~TTrec ()
 int TTrec::compare(const TSortable & a) const
 {
   const TTrec & r = (const TTrec &) a;
-  const int res = memcmp ((const void *) _rec, (const void *) r._rec, sizeof (*_rec));
+  int res = 0;
+  
+  if (_rec->NFields != r._rec->NFields || _rec->NKeys != r._rec->NKeys)  // Confronta prima il numero dei campi o il numero delle chiavi
+    res = 1;
+  else
+  {
+    const int nkeys = _rec->NKeys;
+    for (int i=0; i<nkeys && res==0; i++) // scorre la lista delle chiavi (sono meno del numero di campi)
+    {
+      const KeyDes& k1 = _rec->Ky[i];
+      const KeyDes& k2 = r._rec->Ky[i];
+      if (k1.DupKeys != k2.DupKeys || k1.NkFields != k2.NkFields)
+        res = 1;
+      else
+        for (int j=0; j<k1.NkFields && res==0; j++)
+          if (k1.FieldSeq[j] != k2.FieldSeq[j] || k1.FromCh[j] != k2.FromCh[j]
+              || (k1.FromCh[j] != INVFLD && k1.ToCh[j] != k2.ToCh[j]))
+              res = 1;
+    }
+    
+    if (res == 0) // se sono ancora uguali confronta tutti i campi
+    {
+      const int nflds = _rec->NFields;
+      for (int n=0; n<nflds && res==0; n++)
+      {
+        const RecFieldDes& r1 = _rec->Fd[n];
+        const RecFieldDes& r2 = r._rec->Fd[n];
+        if (r1.TypeF != r2.TypeF || r1.Len != r2.Len || r1.Dec != r2.Dec)
+          res = 1;
+        else
+          if (strcmp(r1.Name,r2.Name) != 0) 
+            res = 1;
+      }
+    }
+  }
   return res; 
 }
 
@@ -570,7 +605,7 @@ void TTrec::update_keydef (int key, const char *desc)
 
         _rec->Ky[key].FieldSeq[n] = i;
         _rec->Ky[key].FromCh[n] = INVFLD;
-        _rec->Ky[key].FromCh[n] = INVFLD;
+        _rec->Ky[key].ToCh[n]   = INVFLD;
         inst = c.step ();
         sym = inst.getsym ();
         if (sym == _upper)
@@ -596,7 +631,7 @@ void TTrec::print_on (ostream & out) const
 {
   const int n = num();
   out << n;
-  if (_des && n>=3 && n<=5) // Solo se e' una tabella...
+  if (_des && n>=LF_TABGEN && n<=LF_TAB && _tab.not_empty()) // Solo se e' una tabella...
     out << "|" << _tab;
   out << '\n';
   const int nfields = fields ();
@@ -628,7 +663,7 @@ void TTrec::read_from (istream & in)
   const int n = num();
 
   in.getline (_files_tmp_string, sizeof (_files_tmp_string), '\n');
-  if (_des && n>=3 && n<=5)
+  if (_des && n>=LF_TABGEN && n<=LF_TAB)
   {
     TString t(_files_tmp_string);
 
diff --git a/include/files.h b/include/files.h
index c40313b3b..a087e17b8 100755
--- a/include/files.h
+++ b/include/files.h
@@ -244,7 +244,7 @@ public:
   const char* keydef(int key) const;
   // @cmember Ritorna la lunghezza del record
   int len() const
-  { return _rec->Fd[fields() - 1].RecOff + _rec->Fd[fields() - 1].Len; }
+  { return fields() > 0 ? _rec->Fd[fields() - 1].RecOff + _rec->Fd[fields() - 1].Len : 0; }
   
 #ifndef FOXPRO
   // @cmember Aggiorna la chiave. <p desc> e' una token string