text: // Copyright (c) 2009-2018 The BitcoinCore developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #include <list>
  #include <locale>
  #include <stdexcept>
  
  namespace
  {
  // trigger: use ctype<char>::widen to trigger ctype<char>::_M_widen_init().
  // test: convert a char from narrow to wide and back. Verify that the result
  //   matches the original.
  bool sanity_test_widen(char testchar)
  {
      const std::ctype<char>& test(std::use_facet<std::ctype<char> >(std::locale()));
      return test.narrow(test.widen(testchar), 'b') == testchar;
  }
  
  // trigger: use list::push_back and list::pop_back to trigger _M_hook and
  //   _M_unhook.
  // test: Push a sequence of integers into a list. Pop them off and verify that
  //   they match the original sequence.
  bool sanity_test_list(unsigned int size)
  {
      std::list<unsigned int> test;
      for (unsigned int i = 0; i != size; ++i)
          test.push_back(i + 1);
  
      if (test.size() != size)
          return false;
  
      while (!test.empty()) {
          if (test.back() != test.size())
              return false;
          test.pop_back();
      }
      return true;
  }
  
  } // namespace
  
  // trigger: string::at(x) on an empty string to trigger __throw_out_of_range_fmt.
  // test: force std::string to throw an out_of_range exception. Verify that
  //   it's caught correctly.
  bool sanity_test_range_fmt()
  {
      std::string test;
      try {
          test.at(1);
      } catch (const std::out_of_range&) {
          return true;
      } catch (...) {
      }
      return false;
  }
  
  bool glibcxx_sanity_test()
  {
      return sanity_test_widen('a') && sanity_test_list(100) && sanity_test_range_fmt();
  }
  