std::basic_filebuf<>: sync() after close() calls __rw_fseek() on closed file

#include <fstream>

int main (int argc, char* argv[])
{
    std::ifstream fs (argv [0], std::ios::binary);
    char c;
    fs.get (c);
    fs.close ();
    fs.sync ();

    return 0;
}

Index: include/fstream.cc
===================================================================
--- include/fstream.cc	(revision 667432)
+++ include/fstream.cc	(working copy)
@@ -106,6 +106,8 @@
             _C_file    = 0;
             _C_cur_pos = _C_beg_pos = pos_type (off_type (-1));
 
+            this->setg(0, 0, 0);
+            this->setp(0, 0);
         }
 
         // rethrow the caught exception
@@ -119,6 +121,9 @@
         // zero out the file pointer except when detaching fd
         _C_file    = 0;
         _C_cur_pos = _C_beg_pos = pos_type (off_type (-1));
+
+        this->setg(0, 0, 0);
+        this->setp(0, 0);
     }
 
     return __retval;