handler_ptr

A smart pointer container with associated completion handler.

Synopsis

Defined in header <boost/beast/core/handler_ptr.hpp>

template<
    class T,
    class Handler>
class handler_ptr

Types

Name	Description
element_type	The type of element this object stores.
handler_type	The type of handler this object stores.

Member Functions

Name	Description
get	Returns a pointer to the owned object.
handler	Returns a reference to the handler.
handler_ptr	Move constructor. Copy constructor. Construct a new handler_ptr.
invoke	Invoke the handler in the owned object.
operator bool	Returns true if *this owns an object.
operator*	Return a reference to the owned object.
operator->	Return a pointer to the owned object.
operator=	Copy assignment (disallowed).
release_handler	Release ownership of the handler.
~handler_ptr	Destructs the owned object if no more handler_ptr link to it.

This is a smart pointer that retains shared ownership of an object through a pointer. Memory is managed using the allocation and deallocation functions associated with a completion handler, which is also stored in the object. The managed object is destroyed and its memory deallocated when one of the following happens:

The function handler_ptr::invoke is called.
The function handler_ptr::release_handler is called.
The last remaining container owning the object is destroyed.

Objects of this type are used in the implementation of composed operations. Typically the composed operation's shared state is managed by the handler_ptr and an allocator associated with the final handler is used to create the managed object.

Remarks

The reference count is stored using a 16 bit unsigned integer. Making more than 2^16 copies of one object results in undefined behavior.

Template Parameters

Type	Description
`T`	The type of the owned object.
`Handler`	The type of the completion handler.

Convenience header <boost/beast/core.hpp>