std::auto_ptr

Langue: en

Autres versions - même langue

Version: 316162 (ubuntu - 07/07/09)

Section: 3 (Bibliothèques de fonctions)

Sommaire

NAME

std::auto_ptr - A simple smart pointer providing strict ownership semantics.

SYNOPSIS


Public Types


typedef _Tp element_type

Public Member Functions


auto_ptr (auto_ptr_ref< element_type > __ref) throw ()

template<typename _Tp1 > auto_ptr (auto_ptr< _Tp1 > &__a) throw ()

auto_ptr (auto_ptr &__a) throw ()

auto_ptr (element_type *__p=0) throw ()

element_type * get () const throw ()

template<typename _Tp1 > operator auto_ptr< _Tp1 > () throw ()

template<typename _Tp1 > operator auto_ptr_ref< _Tp1 > () throw ()

element_type & operator* () const throw ()

element_type * operator-> () const throw ()

auto_ptr & operator= (auto_ptr_ref< element_type > __ref) throw ()

template<typename _Tp1 > auto_ptr & operator= (auto_ptr< _Tp1 > &__a) throw ()

auto_ptr & operator= (auto_ptr &__a) throw ()

element_type * release () throw ()

void reset (element_type *__p=0) throw ()

~auto_ptr ()

Detailed Description

template<typename _Tp> class std::auto_ptr< _Tp >

The Standard says: 
 
   An auto_ptr owns the object it holds a pointer to.  Copying
   an auto_ptr copies the pointer and transfers ownership to the
   destination.  If more than one auto_ptr owns the same object
   at the same time the behavior of the program is undefined.
 

   The uses of auto_ptr include providing temporary
   exception-safety for dynamically allocated memory, passing
   ownership of dynamically allocated memory to a function, and
   returning dynamically allocated memory from a function.  auto_ptr does not meet the CopyConstructible and Assignable
   requirements for Standard Library container elements and thus
   instantiating a Standard Library container with an auto_ptr results in undefined behavior.


 Quoted from [20.4.5]/3.

Good examples of what can and cannot be done with auto_ptr can be found in the libstdc++ testsuite.

Definition at line 174 of file memory.

Member Typedef Documentation

template<typename _Tp> typedef _Tp std::auto_ptr< _Tp >::element_type

The pointed-to type.

Definition at line 181 of file memory.

Constructor & Destructor Documentation

template<typename _Tp> std::auto_ptr< _Tp >::auto_ptr (element_type * __p = 0) throw () [inline, explicit]

An auto_ptr is usually constructed from a raw pointer.

Parameters:

p A pointer (defaults to NULL).

This object now owns the object pointed to by p.

Definition at line 190 of file memory.

template<typename _Tp> std::auto_ptr< _Tp >::auto_ptr (auto_ptr< _Tp > & __a) throw () [inline]

An auto_ptr can be constructed from another auto_ptr.

Parameters:

a Another auto_ptr of the same type.

This object now owns the object previously owned by a, which has given up ownsership.

Definition at line 199 of file memory.

template<typename _Tp> template<typename _Tp1 > std::auto_ptr< _Tp >::auto_ptr (auto_ptr< _Tp1 > & __a) throw () [inline]

An auto_ptr can be constructed from another auto_ptr.

Parameters:

a Another auto_ptr of a different but related type.

A pointer-to-Tp1 must be convertible to a pointer-to-Tp/element_type.

This object now owns the object previously owned by a, which has given up ownsership.

Definition at line 212 of file memory.

template<typename _Tp> std::auto_ptr< _Tp >::~auto_ptr () [inline]

When the auto_ptr goes out of scope, the object it owns is deleted. If it no longer owns anything (i.e., get() is NULL), then this has no effect.

Definition at line 259 of file memory.

template<typename _Tp> std::auto_ptr< _Tp >::auto_ptr (auto_ptr_ref< element_type > __ref) throw () [inline]

Automatic conversions.

These operations convert an auto_ptr into and from an auto_ptr_ref automatically as needed. This allows constructs such as

     auto_ptr<Derived>  func_returning_auto_ptr(.....);
     ...
     auto_ptr<Base> ptr = func_returning_auto_ptr(.....);


 

Definition at line 349 of file memory.

Member Function Documentation

template<typename _Tp> element_type* std::auto_ptr< _Tp >::get (void) const throw () [inline]

Bypassing the smart pointer.

Returns:

The raw pointer being managed.

You can get a copy of the pointer that this object owns, for situations such as passing to a function which only accepts a raw pointer.

Note:

This auto_ptr still owns the memory.

Definition at line 300 of file memory.

template<typename _Tp> element_type& std::auto_ptr< _Tp >::operator* () const throw () [inline]

Smart pointer dereferencing.

If this auto_ptr no longer owns anything, then this operation will crash. (For a smart pointer, 'no longer owns anything' is the same as being a null pointer, and you know what happens when you dereference one of those...)

Definition at line 270 of file memory.

template<typename _Tp> element_type* std::auto_ptr< _Tp >::operator-> () const throw () [inline]

Smart pointer dereferencing.

This returns the pointer itself, which the language then will automatically cause to be dereferenced.

Definition at line 283 of file memory.

template<typename _Tp> template<typename _Tp1 > auto_ptr& std::auto_ptr< _Tp >::operator= (auto_ptr< _Tp1 > & __a) throw () [inline]

auto_ptr assignment operator.

Parameters:

a Another auto_ptr of a different but related type.

A pointer-to-Tp1 must be convertible to a pointer-to-Tp/element_type.

This object now owns the object previously owned by a, which has given up ownsership. The object that this one used to own and track has been deleted.

Definition at line 241 of file memory.

template<typename _Tp> auto_ptr& std::auto_ptr< _Tp >::operator= (auto_ptr< _Tp > & __a) throw () [inline]

auto_ptr assignment operator.

Parameters:

a Another auto_ptr of the same type.

This object now owns the object previously owned by a, which has given up ownsership. The object that this one used to own and track has been deleted.

Definition at line 223 of file memory.

template<typename _Tp> element_type* std::auto_ptr< _Tp >::release () throw () [inline]

Bypassing the smart pointer.

Returns:

The raw pointer being managed.

You can get a copy of the pointer that this object owns, for situations such as passing to a function which only accepts a raw pointer.

Note:

This auto_ptr no longer owns the memory. When this object goes out of scope, nothing will happen.

Definition at line 314 of file memory.

template<typename _Tp> void std::auto_ptr< _Tp >::reset (element_type * __p = 0) throw () [inline]

Forcibly deletes the managed object.

Parameters:

p A pointer (defaults to NULL).

This object now owns the object pointed to by p. The previous object has been deleted.

Definition at line 329 of file memory.

Author

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