gcc/libstdc++-v3/libsupc++/new_opnt.cc
Jonathan Wakely c227d96feb libstdc++: Add comment to nothrow new explaining catch (...)
The decision to not rethrow a __forced_unwind exception is deliberate,
so add a comment explaining it.

libstdc++-v3/ChangeLog:

	* libsupc++/new_opnt.cc (new): Add comment about forced unwind
	exceptions.
2020-10-28 13:19:21 +00:00

53 lines
1.9 KiB
C++

// Support routines for the -*- C++ -*- dynamic memory management.
// Copyright (C) 1997-2020 Free Software Foundation, Inc.
//
// This file is part of GCC.
//
// GCC 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 3, or (at your option)
// any later version.
//
// GCC 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.
//
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
#include <bits/c++config.h>
#include <bits/exception_defines.h>
#include "new"
extern "C" void *malloc (std::size_t);
_GLIBCXX_WEAK_DEFINITION void *
operator new (std::size_t sz, const std::nothrow_t&) noexcept
{
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 206. operator new(size_t, nothrow) may become unlinked to ordinary
// operator new if ordinary version replaced
__try
{
return ::operator new(sz);
}
__catch (...)
{
// N.B. catch (...) means the process will terminate if operator new(sz)
// exits with a __forced_unwind exception. The process will print
// "FATAL: exception not rethrown" to stderr before exiting.
//
// If we propagated that exception the process would still terminate
// (because this function is noexcept) but with a less informative error:
// "terminate called without active exception".
return nullptr;
}
}