--- ddrescue-1.14/main.cc	2011-01-10 20:54:14.000000000 +0200
+++ ddrescue-1.14-checksamefile/main.cc	2011-05-20 13:24:38.875108290 +0300
@@ -573,6 +573,8 @@
   if( argind < parser.arguments() ) iname = parser.argument( argind++ ).c_str();
   if( argind < parser.arguments() ) oname = parser.argument( argind++ ).c_str();
   if( argind < parser.arguments() ) logname = parser.argument( argind++ ).c_str();
+  if( strcmp(oname, logname) == 0)
+    { show_error( "Output file and log file are the same file." ); return 1; }
   if( argind < parser.arguments() )
     { show_error( "Too many files.", 0, true ); return 1; }