libstdc++
std::auto_ptr Class Reference

List of all members.

Public Types

Public Member Functions


Detailed Description

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

The pointed-to type.

Definition at line 94 of file auto_ptr.h.


Constructor & Destructor Documentation

std::auto_ptr::auto_ptr ( element_type __p = 0) throw () [inline, explicit]

An auto_ptr is usually constructed from a raw pointer.

Parameters:
pA pointer (defaults to NULL).

This object now owns the object pointed to by p.

Definition at line 103 of file auto_ptr.h.

std::auto_ptr::auto_ptr ( auto_ptr __a) throw () [inline]

An auto_ptr can be constructed from another auto_ptr.

Parameters:
aAnother auto_ptr of the same type.

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

Definition at line 112 of file auto_ptr.h.

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

An auto_ptr can be constructed from another auto_ptr.

Parameters:
aAnother 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.

Definition at line 125 of file auto_ptr.h.

std::auto_ptr::~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

Definition at line 170 of file auto_ptr.h.

std::auto_ptr::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 260 of file auto_ptr.h.


Member Function Documentation

element_type* std::auto_ptr::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 211 of file auto_ptr.h.

element_type& std::auto_ptr::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 181 of file auto_ptr.h.

element_type* std::auto_ptr::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 194 of file auto_ptr.h.

auto_ptr& std::auto_ptr::operator= ( auto_ptr __a) throw () [inline]

auto_ptr assignment operator.

Parameters:
aAnother 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.

Definition at line 136 of file auto_ptr.h.

References reset().

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

auto_ptr assignment operator.

Parameters:
aAnother 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.

Definition at line 154 of file auto_ptr.h.

References reset().

element_type* std::auto_ptr::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 225 of file auto_ptr.h.

void std::auto_ptr::reset ( element_type __p = 0) throw () [inline]

Forcibly deletes the managed object.

Parameters:
pA pointer (defaults to NULL).

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

Definition at line 240 of file auto_ptr.h.

Referenced by operator=().


The documentation for this class was generated from the following file: