new头文件 – 梁笔记

new头文件中也定义了内存异常类bad_alloc，用来处理new/delete出错时处理。

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// The -*- C++ -*- dynamic memory management header.

// Free Software Foundation

// 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 2, 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.

// You should have received a copy of the GNU General Public License

// along with GCC; see the file COPYING. If not, write to

// the Free Software Foundation, 59 Temple Place - Suite 330,

// Boston, MA 02111-1307, USA.

// As a special exception, you may use this file as part of a free software

// library without restriction. Specifically, if other files instantiate

// templates or use macros or inline functions from this file, or you compile

// this file and link it with other files to produce an executable, this

// file does not by itself cause the resulting executable to be covered by

// the GNU General Public License. This exception does not however

// invalidate any other reasons why the executable file might be covered by

// the GNU General Public License.

/** @file new

* The header @c new defines several functions to manage dynamic memory and

* handling memory allocation errors; see

* http://gcc.gnu.org/onlinedocs/libstdc++/18_support/howto.html#4 for more.

#ifndef _NEW

#define _NEW

#include <cstddef>

#include <exception>

extern "C++" {

namespace std

{

/**

* @brief Exception possibly thrown by @c new.

* @c bad_alloc (or classes derived from it) is used to report allocation

* errors from the throwing forms of @c new. */

class bad_alloc : public exception

{

public:

bad_alloc() throw() { }

// This declaration is not useless:

// http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118

virtual ~bad_alloc() throw();

};

struct nothrow_t { };

extern const nothrow_t nothrow;

/** If you write your own error handler to be called by @c new, it must

* be of this type. */

typedef void (*new_handler)();

/// Takes a replacement handler as the argument, returns the previous handler.

new_handler set_new_handler(new_handler) throw();

} // namespace std

//@{

/** These are replaceable signatures:

* - normal single new and delete (no arguments, throw @c bad_alloc on error)

* - normal array new and delete (same)

* - @c nothrow single new and delete (take a @c nothrow argument, return

* @c NULL on error)

* - @c nothrow array new and delete (same)

* Placement new and delete signatures (take a memory address argument,

* does nothing) may not be replaced by a user's program.

void* operator new(std::size_t) throw (std::bad_alloc);

void* operator new[](std::size_t) throw (std::bad_alloc);

void operator delete(void*) throw();

void operator delete[](void*) throw();

void* operator new(std::size_t, const std::nothrow_t&) throw();

void* operator new[](std::size_t, const std::nothrow_t&) throw();

void operator delete(void*, const std::nothrow_t&) throw();

void operator delete[](void*, const std::nothrow_t&) throw();

// Default placement versions of operator new.

inline void* operator new(std::size_t, void* __p) throw() { return __p; }

inline void* operator new[](std::size_t, void* __p) throw() { return __p; }

// Default placement versions of operator delete.

inline void operator delete (void*, void*) throw() { }

inline void operator delete[](void*, void*) throw() { }

//@}

} // extern "C++"

#endif

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