Class scoped_array stores a pointer to a dynamically allocated array. (Dynamically allocated arrays are allocated with the C++ new[] expression.) The array pointed to is guaranteed to be deleted, either on destruction of the scoped_array, or via an explicit scoped_array::reset().
Class scoped_array is a simple solution for simple needs. It cannot be used in C++ Standard Library containers. See shared_array if scoped_array does not meet your needs.
Class scoped_array cannot correctly hold a pointer to a single object. See scoped_ptr for that usage.
Because scoped_array is so simple, in its usual implementation every operation is as fast as a built-in array pointer and has no more space overhead that a built-in array pointer.
A heavier duty alternative to a scoped_array is a scoped_ptr to a C++ Standard Library vector.
The class is a template parameterized on T, the type of the object pointed to. T must meet the smart pointer common requirements.
#include <boost/smart_ptr.hpp> namespace boost { template<typename T> class scoped_array : noncopyable { public: typedef T element_type; explicit scoped_array( T* p=0 ); // never throws ~scoped_array(); void reset( T* p=0 ); T& operator[](std::size_t i) const; // never throws T* get() const; // never throws }; }
typedef T element_type;
Provides the type of the stored pointer.
explicit scoped_array( T* p=0 ); // never throws
Constructs a scoped_array, storing a copy of p, which must have been allocated via a C++ new[] expression or be 0.
~scoped_array();
Deletes the array pointed to by the stored pointer. Note that in C++ delete[] on a pointer with a value of 0 is harmless.
Does not throw exceptions.
void reset( T* p=0 )();
If p is not equal to the stored pointer, deletes the array pointed to by the stored pointer and then stores a copy of p, which must have been allocated via a C++ new[] expression or be 0.
Does not throw exceptions.
T& operator[](std::size_t i) const; // never throws
Returns a reference to element i of the array pointed to by the stored pointer.
Behavior is undefined (and almost certainly undesirable) if get()==0, or if i is less than 0 or is greater or equal to the number of elements in the array.
T* get() const; // never throws
Returns the stored pointer.
[To be supplied. In the meantime, see smart_ptr_test.cpp.]
Revised December 8, 1999
© Copyright Greg Colvin and Beman Dawes 1999. Permission to copy, use, modify, sell and distribute this document is granted provided this copyright notice appears in all copies. This document is provided "as is" without express or implied warranty, and with no claim as to its suitability for any purpose.