text: // 2000-06-29 bkoz
  
  // Copyright (C) 2000, 2001, 2002, 2003 Free Software Foundation
  //
  // This file is part of the GNU ISO C++ Library.  This library is free
  // software; you can redistribute it and/or modify it under the
  // terms of the GNU General Public License as published by the
  // Free Software Foundation; either version 2, or (at your option)
  // any later version.
  
  // This library is distributed in the hope that it will be useful,
  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  // GNU General Public License for more details.
  
  // You should have received a copy of the GNU General Public License along
  // with this library; see the file COPYING.  If not, write to the Free
  // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  // USA.
  
  // 27.6.1.3 unformatted input functions
  // NB: ostream has a particular "seeks" category. Adopt this for istreams too.
  // @require@ %-*.tst %-*.txt
  // @diff@ %-*.tst %-*.txt
  
  #include <istream>
  #include <sstream>
  #include <fstream>
  #include <testsuite_hooks.h>
  
  // fstreams
  void test04(void)
  {
    typedef std::istream::off_type off_type;
  
    bool test __attribute__((unused)) = true;
    std::istream::pos_type pos01, pos02, pos03, pos04, pos05, pos06;
    std::ios_base::iostate state01, state02;
    const char str_lit01[] = "istream_seeks-1.txt";
    const char str_lit02[] = "istream_seeks-2.txt";
    std::ifstream if01(str_lit01, std::ios_base::in | std::ios_base::out);
    std::ifstream if02(str_lit01, std::ios_base::in);
    std::ifstream if03(str_lit02, std::ios_base::out | std::ios_base::trunc); 
    VERIFY( if01.good() );
    VERIFY( if02.good() );
    VERIFY( if03.good() );
  
    std::istream is01(if01.rdbuf());
    std::istream is02(if02.rdbuf());
    std::istream is03(if03.rdbuf());
  
    pos01 = is01.tellg();
    pos02 = is01.tellg();
    pos03 = is02.tellg();
    pos04 = is02.tellg();
    pos05 = is03.tellg();
    pos06 = is03.tellg();
  
    // istream& seekg(pos_type)
    // istream& seekg(off_type, ios_base::seekdir)
  
    // cur 
    // NB: see library issues list 136. It's the v-3 interp that seekg
    // only sets the input buffer, or else istreams with buffers that
    // have _M_mode == ios_base::out will fail to have consistency
    // between seekg and tellg.
    state01 = is01.rdstate();
    is01.seekg(10, std::ios_base::cur);
    state02 = is01.rdstate();
    pos01 = is01.tellg(); 
    VERIFY( pos01 == pos02 + off_type(10) ); 
    VERIFY( state01 == state02 );
    pos02 = is01.tellg(); 
    VERIFY( pos02 == pos01 ); 
  
    state01 = is02.rdstate();
    is02.seekg(10, std::ios_base::cur);
    state02 = is02.rdstate();
    pos03 = is02.tellg(); 
    VERIFY( pos03 == pos04 + off_type(10) ); 
    VERIFY( state01 == state02 );
    pos04 = is02.tellg(); 
    VERIFY( pos03 == pos04 ); 
  
    state01 = is03.rdstate();
    is03.seekg(10, std::ios_base::cur);
    state02 = is03.rdstate();
    pos05 = is03.tellg(); 
    VERIFY( pos05 == pos06 + off_type(10) ); 
    VERIFY( state01 == state02 );
    pos06 = is03.tellg(); 
    VERIFY( pos05 == pos06 ); 
  
    // beg
    state01 = is01.rdstate();
    is01.seekg(20, std::ios_base::beg);
    state02 = is01.rdstate();
    pos01 = is01.tellg(); 
    VERIFY( pos01 == pos02 + off_type(10) ); 
    VERIFY( state01 == state02 );
    pos02 = is01.tellg(); 
    VERIFY( pos02 == pos01 ); 
  
    state01 = is02.rdstate();
    is02.seekg(20, std::ios_base::beg);
    state02 = is02.rdstate();
    pos03 = is02.tellg(); 
    VERIFY( pos03 == pos04 + off_type(10) ); 
    VERIFY( state01 == state02 );
    pos04 = is02.tellg(); 
    VERIFY( pos03 == pos04 ); 
  
    state01 = is03.rdstate();
    is03.seekg(20, std::ios_base::beg);
    state02 = is03.rdstate();
    pos05 = is03.tellg(); 
    VERIFY( pos05 == pos06 + off_type(10) );
    VERIFY( state01 == state02 );
    pos06 = is03.tellg(); 
    VERIFY( pos05 == pos06 );
  }
  
  int main()
  {
    test04();
    return 0;
  }
  