libstdc++-v3/libsupc++/new_opnt.cc

   1 // Support routines for the -*- C++ -*- dynamic memory management.
   2 // Copyright (C) 1997-2018 Free Software Foundation, Inc.
   3 //
   4 // This file is part of GCC.
   5 //
   6 // GCC is free software; you can redistribute it and/or modify
   7 // it under the terms of the GNU General Public License as published by
   8 // the Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10 //
  11 // GCC is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15 //
  16 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 #include <bits/c++config.h>
  26 #include <bits/exception_defines.h>
  27 #include "new"
  28
  29 using std::new_handler;
  30 using std::bad_alloc;
  31
  32 extern "C" void *malloc (std::size_t);
  33
  34 _GLIBCXX_WEAK_DEFINITION void *
  35 operator new (std::size_t sz, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
  36 {
  37   void *p;
  38
  39   /* malloc (0) is unpredictable; avoid it.  */
  40   if (sz == 0)
  41     sz = 1;
  42
  43   while (__builtin_expect ((p = malloc (sz)) == 0, false))
  44     {
  45       new_handler handler = std::get_new_handler ();
  46       if (! handler)
  47         return 0;
  48       __try
  49         {
  50           handler ();
  51         }
  52       __catch(const bad_alloc&)
  53         {
  54           return 0;
  55         }
  56     }
  57
  58   return p;
  59 }