std::auto_ptr< _Tp >(3cxx) std::auto_ptr< _Tp >(3cxx)
NAME
std::auto_ptr< _Tp > - A simple smart pointer providing strict
ownership semantics.
SYNOPSIS
Public Types
typedef _Tp element_type
The pointed-to type.
Public Member Functions
auto_ptr (auto_ptr &__a) throw ()
An auto_ptr can be constructed from another auto_ptr.
template<typename _Tp1 > auto_ptr (auto_ptr< _Tp1 > &__a) throw ()
An auto_ptr can be constructed from another auto_ptr.
auto_ptr (auto_ptr_ref< element_type > __ref) throw ()
Automatic conversions.
auto_ptr (element_type *__p=0) throw ()
An auto_ptr is usually constructed from a raw pointer.
~auto_ptr ()
element_type * get () const throw ()
Bypassing the smart pointer.
template<typename _Tp1 > operator auto_ptr< _Tp1 > () throw ()
template<typename _Tp1 > operator auto_ptr_ref< _Tp1 > () throw ()
element_type & operator* () const throw ()
Smart pointer dereferencing.
element_type * operator-> () const throw ()
Smart pointer dereferencing.
auto_ptr & operator= (auto_ptr &__a) throw ()
auto_ptr assignment operator.
template<typename _Tp1 > auto_ptr & operator= (auto_ptr< _Tp1 > &__a)
throw ()
auto_ptr assignment operator.
auto_ptr & operator= (auto_ptr_ref< element_type > __ref) throw ()
element_type * release () throw ()
Bypassing the smart pointer.
void reset (element_type *__p=0) throw ()
Forcibly deletes the managed object.
Detailed Description
template<typename _Tp>
class std::auto_ptr< _Tp >" A simple smart pointer providing strict
ownership semantics.
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.
_GLIBCXX_RESOLVE_LIB_DEFECTS
127.
auto_ptr<> conversion issues These resolutions have all been
incorporated.
Member Typedef Documentation
template<typename _Tp > typedef _Tp std::auto_ptr< _Tp >::element_type
The pointed-to type.
Constructor & Destructor Documentation
template<typename _Tp > std::auto_ptr< _Tp >::auto_ptr (element_type * __p
= 0) [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.
template<typename _Tp > std::auto_ptr< _Tp >::auto_ptr (auto_ptr< _Tp > &
__a) [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 ownership.
template<typename _Tp > template<typename _Tp1 > std::auto_ptr< _Tp
>::auto_ptr (auto_ptr< _Tp1 > & __a) [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 ownership.
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.
The C++ standard says there is supposed to be an empty throw
specification here, but omitting it is standard conforming. Its
presence can be detected only if _Tp::~_Tp() throws, but this is
prohibited. [17.4.3.6]/2
template<typename _Tp > std::auto_ptr< _Tp >::auto_ptr (auto_ptr_ref<
element_type > __ref) [inline]
Automatic conversions. These operations are supposed to convert an
auto_ptr into and from an auto_ptr_ref automatically as needed. This
would allow constructs such as
auto_ptr<Derived> func_returning_auto_ptr(.....);
...
auto_ptr<Base> ptr = func_returning_auto_ptr(.....);
But it doesn't work, and won't be fixed. For further details see
http://cplusplus.github.io/LWG/lwg-closed.html#463
Member Function Documentation
template<typename _Tp > element_type* std::auto_ptr< _Tp >::get (void)
const [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.
template<typename _Tp > element_type& std::auto_ptr< _Tp >::operator* ()
const [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...)
template<typename _Tp > element_type* std::auto_ptr< _Tp >::operator-> ()
const [inline]
Smart pointer dereferencing. This returns the pointer itself, which the
language then will automatically cause to be dereferenced.
template<typename _Tp > auto_ptr& std::auto_ptr< _Tp >::operator=
(auto_ptr< _Tp > & __a) [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 ownership. The object that this one used to own and track has
been deleted.
References std::auto_ptr< _Tp >::reset().
template<typename _Tp > template<typename _Tp1 > auto_ptr& std::auto_ptr<
_Tp >::operator= (auto_ptr< _Tp1 > & __a) [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 ownership. The object that this one used to own and track has
been deleted.
References std::auto_ptr< _Tp >::reset().
template<typename _Tp > element_type* std::auto_ptr< _Tp >::release ()
[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.
template<typename _Tp > void std::auto_ptr< _Tp >::reset (element_type *
__p = 0) [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.
Referenced by std::auto_ptr< _Tp >::operator=().
Author
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libstdc++ Sat May 13 2023 std::auto_ptr< _Tp >(3cxx)
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